Other than the elevation disc (8/3 vs 6/3), are there any other changes between carbine A2 rears and rifle A2 rears?

I put together an A2 upper to recreate a Colt R0733 upper that I had foolishly sold (I don't remember if it had M4 feed ramps, but the one I built does ) - it wasn't until I got it to the range to do initial break in and zero that I realized that the A2 rear was an 8/3 disc...it should probably be a 6/3.

Do I need to yank the whole thing and replace with a new unit, or just swap out the disc...if I can find one

At this rate it might be easier/cheaper/faster to buy a detachable carry handle with sight intact, and cannibalize that..

At rifle radius, the A2 sight has 1 MOA elevation clicks, the detachable carry handle has 0.5 MOA elevation clicks. The detachable is 6/3 because the shaft is shorter.

Ahh! Ok! I feel less bad then

Thank you!

Now to figure out why an M16A1/604 clone upper I just slapped together with a surplus Colt upper and a Brownells 20" retro barrel assembly needed the front sight buried and the windage drum pinned all the way to the left to zero it at 50 yards with the L aperature in place...I'm probably gonna be yanking that one back apart, sigh

The windage issue could come from an over torqued barrel nut
Do you have A1 sights or A2. Your title says A2 but them you say you have an A1 upper.  For A1 sights you're supposed to zero at 25 with the L aperture them flip to the unmarked one for under 300m use

One statement has nothing to do with the other; totally different upper. The barrel nut isn't overtorqued for sure; I doubt it's got more than 50lb on it.