Couple of 'hints'...sort of.
Look at 'coring bits' for the flash hider, there are hundreds of different brands and designs, and the ones used 'back then' likley looked different than the ones you see now.
Modern Core bits:
As for the Trigger clevis or the actual tube the rod runs through, look around for spigot type rifle grenade launchers, they have a very similar size and shape. People assume it's larger than it is but it's only about 7 inches long by 7/8 inch at the most.
AK Spigot:
Now...go hit those junk shops!
M