Much more posts on trigger packs over at the FN forum, but got tired of some of the crazies over there.  So posting my info here as well.
As far as owners can tell, FN PS90s come with three different trigger packs.  No forth gen trigger pack with missing "auto sear" has been confirmed as coming from FN that way.
Generation 1 and 2 trigger packs function the same and the difference is the coloration in the plastics.  Generation 3 trigger packs have a different cut in the hammer and also do not have the shelf cut on the "hammer sear".

Here are some photos of a stock Gen 2 trigger pack:

Ignore the arrow pointing to the removable pin.
And for sure forget you ever saw the second arrow pointing to where the spring rests on the "hammer sear".

Here are some photos of a stock Gen 3 trigger pack:



Here are some photos of a Gen 3 trigger pack with easily available and cheap standard Steyr Aug hammer:

To make the hammers work in the trigger pack you just need to remove excess plastic from the hole the guide pin goes through as well as slightly widen the hole.  Not bad for a $35 part  :)


Here are some photos of a Gen 3 trigger pack fully modified to function just like a Gen 1/2 trigger pack.  It has the Aluminum hammer as well as the shelf trimmed out of the "hammer sear".



While we may see droughts of several months with nothing available, Midwest Gun Works will usually have trigger packs in stock eventually.  No need to spend big money on a Gen 3 on GunBroker if you can hold out :)

Man Kave also now makes their "Gen 1" reduced pull hammer in plastic as well :D

So would a man kave hammer and sear make a gen 3 trigger pack essentially a gen 1 pack?

ETA I was thinking about this upgrade for mine as I bought the ps90 for my wife and thought the reduced pull might be a benefit for her

No sears required on a gen 3 trigger pack.  A hammer will get you halfway, the "hammer sear" would need material removed to give it that shelf that Gen 1/2 trigger packs have.

What's the best way to get the "hammer sear" out with that blind pin in place?

I know of no good way to get that pin out.  Also no good reason to mess with it.  Now, all the other pins; including the "hammer sear" pin; are removable.

I thought FN had to remove the "safety sear" from their trigger packs?

what's that shelf cut on the "hammer sear" do?

Yes I'm referring to the Auto Sear.  When the controversy started about the "Auto Sear" everyone was calling it a "Safety Sear" because FN left it in for supposedly safety reasons.  Honestly I haven't kept up with the issue so I didn't know it was vogue to call it what it is "Auto Sear" now.

All you have to do to commit a felony is disable a spring...  That's why I thought the trigger packs has been neutered by FN.

I thought they also neutered the "sear trip" surface of the bolt on the later (latest?) generations?

On the bolt? No. That's still required to move the sear out of the way so the hammer can fully fall.

They changed the location that the "safety sear" engages on the hammer though.

I'm still not sure what that ledge on the hammer sear does or why it was removed in the latest gen pack.

Ok good. Thanks.

Do they still ship with the anti-bounce weight installed?

If they altered the sear's geometry, I assume it'd be so it wouldn't function to catch the hammer (perhaps even if a P90 hammer was retrofitted into place)?

The reason the shelf location on the PS90 hammer was modified is so there won't be enough energy to fire if released from that position.

The PS90 bolt (with gen 3 trigger pack) has the anti-bounce weight.

The PS90 bolt will function with a full auto trigger pack. A gunsmith I know did it. (He was legally able to buy the full auto trigger pack)

The modifications required were the new safety (to allow the trigger to go fully rearward). And the trigger pack needed a small piece cut out because the PS90 receiver has a little tab to prevent the FA trigger pack from being installed. (That horizontal cutout can be seen in OP's 1st pic on the left side of the pack).

ETA: And yes I'm guessing they changed the "safety sear" notch on the hammer so if the hammer is released from that point there isn't enough energy to fire.

Nice.

Yeah, legally they could sell a P90 hammer pack to anyone (which doesn't mean they will, of course).

The P90 hammer pack is not a MG until it's modified to fit in the PS90 stock (although I've heard an unmodified P90 stock will fit a PS90 receiver. If that's true then nothing would necessarily require modification, but you'd run into that whole collection of parts definition of a MG, obviously).

I have it on good authority that that weight which is part of the 'moving parts group' (seriously, that's it's name) is the same for the p90 as it is for the ps90.  It's purpose for the p90 is to control (reduce?) the rate of fire.  Not sure what it does for a semi-auto system except maybe reduce recoil a bit?

It doesn't reduce recoil. It's an anti-bounce weight, so it's there to alleviate bolt bounce (which can still be a factor in a semi-auto, if you pull the trigger fast enough).

Because the reduced weight resulting from its removal increases bolt velocity, right?
But why would anyone remove it in the first place?

Or is mag popping still a problem with the standard weight when using certain ammo?

Does said ammo perform extra awesome?

Tungsten... nice.
Seems to be unavailable however.

https://eliteammunition.com/PS90-P90-Heavy-Duty-Tungsten-Rate-Reducer-p51257578

He does specific runs of them in batches as the creation of them tears up his tooling.

Thank you.

There's actually I guy on one of the FB who has mag popping suppressed or unsuppressed shooting factory ammo. He has like 5-6K through the gun and it only started doing it. We speculate the stock may be to blame, but not sure. He has EA's extra power mag spring, Man Kave Mag release, and even Jay's weight. I am not sure if the weight is helping or hurting as another 5.7 friend had his thoughts about mag popping