Choate makes, or at least made, non folding pistol grip stocks for the M-1 carbine. I believe they only fit military and/ or guns made to mil-specs. You would need to contact the mfgr to find out if it would work with your gun. It was filled in in the rear, and was not made to look like a paratrooper carbine stock.
Also, there is a muzzle check and a bell-type flash hider made for the M-1 carbine. They are clamp pn, but prevent bayonet usage when installed.