Hi I have a GM (Inland) m1 it has an underfold stock. A part on the stock recently broke and I am looking for a replacement. the part in question is a round piece of about 12 awg steel that rotates and provides the locking mechanism. I have searched everywhere and no one has even heard of an m1 w/ an underfolding stock. Is this an aftermarket piece (if so it is really well done) or is it something rare. on the barrel just behind the front sight it says inland mfg. div general motors 8-44, behind the rear sight it says inland division 5460789, in front of the bolt it says us carbine cal. 30 m1 and on the rear sight itself it says PI. any help in finding a replacement part or any information about this gun would be greatly appreciated.