NYC Airsoft

I was working on a G&G Combat Machine with missing screws in the RIS for a team mate. I was able to make that solid with some new allen screws and tightening the delta ring. I then went to test fire the gun only to find I could not fill the mags with BBs. The BBs would go in and come right out. I noticed the follower was coming way out. Below are pictures of the mags with Red Arrows pointing at the mag feed lip and what looks like a missing part.


*Note that it is missing off both mags and I am not sure if I lost that or I was given the mags this way.


It looks like a piece is missing on the feed tube. As I have limited experience with Gas Mags, would this be a 'Closed Bolt' mag? Can spare parts be bought to fix this? I am currently abusing Mark Twain on here for help, but any other ideas would be helpful.

Sorry for the large images.