In the early 60's we all carried M-14's in Germanyand I never saw a select fire one. All were semi autos. My son ownes Springfield Inc
M1Athat was factory made select fire with paper. It's worth about $14K I think. The same holds true for the M-2 Carbines, even semi autos are No-No's. We have a M1 Carbine, rebuilt by RIA as a M2 with paper, worth $8K? In short no matter what the gun does, if it is stamped
M-14 or M2 stay away from it if it has no Class 3 paperwork. The best you can do is to strip the gun, sell the parts, and bury the receiver.
Good luck.