Andy
Most of what I have read states made in Kentucky by a firm trying to get military contract in the mid late 70s.
There should be a number and letter mark on the backside of the grip.
They have made many repos afterb that. Gunnyssurplus had then for 20 some bucks a while back.
If you look at them there are differences.
The one here has a round injection mark near the guard. Most I have seen have no such mark.
A search of m7 knuckle bayonet will bring up many forum discussions and photos of these.
The supposed originals are worth about 50 to 80 bucks, repos for 30 to 50, my opinion and findings.
There are reports of brass ones, I have not seen those personally. I believe the rumor plastic ones to be false rumor, and was reference to the original plastic grip.
Hope this sheds SOME light,
Ed
