Does anyone have a source for the sling mount for the trap door style?  Will a a2 sling mount  and screw work? And is there a lot of different style of a1 buttstock?

Pretty sure the A1 & A2 sling mount & screw are the same.

Sling mount the same, but I think the screws for the sling are different.  I think A1 is longer by about 3/4".

Double.

Maybe the wtb section of the EE



Differences

Different length my friend

And there are like 5 types. A-e

The swivels for the A1 and A2 are the same.

The A1 screws are longer.  Fulton has them for $3.95.

There needs to be a thread of links for people to see a list of vendors that sell common parts.

That would be nice, but someone would have to maintain it.

I get the swivels from Brownells

That is right. I forgot about the sling mount on the A1 being placed further forward on the stock than the A2.

I was mainly looking for info on differences between them but also maybe some online sellers that had them. Thanks for the info also.
I'm building a retro look alike I have a c7 upper I found a good deal on. I didn't want to pay for a a1 upper because of the prices of a original and brownells out of stock. Other than the c7 upper everything else is basically to spec of a m16a1. My uncle found a deal on a sp1, he traded a colt m&p sport II  for a near mint 68 sp1 and I couldn't believe how light and well it shot. Soo I had to have a vintage pencil barrel rifle.