I've been looking for a underfolder and was wondering if I take a thumbhole stocked mak90 that has the rear receiver dimples for a underfolder assembly provision, do I need to get a rear trunnion or are they already included in the receiver?
I've seen several mak90's that has the familiar "cross" at the rear, but I don't know if they have a rear trunnion that has the hole for the underfolder option. Thanks!

Next would be tracking down a u.f.'g assembly w/o going into hock!