I took apart a somewhat beat up A1 upper I had aquired to refinish it with some gunkote.  Unfortunately, it looks like I missed a part when I took off the rear site - when I turned the upper over, I heard it hit the floor and skitter off and now it is MIA.  Not exactly sure what it was as I'm not familiar with the A1 rear site assembly, but now the aperture just sort of flops around.  Some kind of spring or ball detent, I'm guessing?

Anywho, does anyone know where I can find a schematic online?  All the ones I've been able to dig up so far are A2 uppers.  Or is anyone familiar with what I actually lost, if it could be fabricated or where I could get a replacement?  Figure Numerich will have what I need, but I need to know what I need first!

Thanks,
Rocko