Not home-made. The upper one is a British Sten gun, standard commando arm in WW II. The bottom one looks like a US-made, GI M-3 "grease gun". Both are easy-to-mass-produce squad automatic weapons intended for CQB. The M-3 was, I think, an Army weapon; I don't think I've ever heard of Marines being issued that weapon. Others will correct me if that's wrong.
Thank you.
Explains why the US made one looks like it was stamped out of sheet metal
I have spent time with an M-3 and I do not believe that is an M-3.
The grip on an M-3 is all the way back.