Bertfish
Throw bread on me
I've eyeballed the receiver shape for a while (I have one of the kits.) One could make a HK collapsible stock fit as a reasonable facsimile if you made a receiver endcap (and if you can weld the receiver 'flat' then yuo have the skills to weld up an endcap.) I can't remember if the 'leg' width was right but it was close. Then just have to cut a barrel down and rethread. The fore-end appears the same in all 3 variants.
Hmmm I think one of my relatives has a set of regular HK furniture. Of course I'd need a CETME receiver to compare it to