Please help me identify these parts:
11.5" Commando Upper it has the markings L M under the rear site (what would this be worth.$.?)
FCG: the hammer has a circle with a line through it and a circle with the #10 inside.
The upper receiver marked LM was made by Martin Marietta, who had the US government contract for spare uppers during the Vietnam era. This means your upper was built up from surplus spare parts and it's difficult to determine what it's worth without more information like who manufactured the barrel and bolt carrier parts. I have no information abouth the markings on your hammer.