Please Identify!

My father and I were out hiking in some of Patton’s old training camps in the Mojave and found a couple items we couldn’t quite identify. You guys identified a few artifacts for me in the past so I was hoping you could give these a shot: One is what we think might be part of a rifle grenade but we haven’t found any pictures online of this exact piece to make a positive identification. The other is some kind of lid that says M-91 Container which we also have not been able to identify. Thanks in advance!

It looks to me like the stabilzer fin from a Ground Signal. Launched from a rifle or carbine grenade launcher. The “GP” would designate it as a Green Star w/Parachute.

That’s my guess, anyway. Pepper probably has a complete set of all colors in his collection. :-)

Not sure if the container lid is related.