Curious why you are calling your M1 Carbine an "Inland/GM" carbine. Are you going by the barrel marking?
FYI: Inland was the largest of ten total manufacturers of the U.S. .30 Cal. M1 Carbine. General Motors (more specifically Saginaw Steering and Gear) did manufacture carbine receivers too (Saginaw marked) but only for a brief period making certain versions among the rarest carbines.
Also, GM itself also made barrels for general issue to other carbine manufacturers and these were all marked with the words "General Motors" as well as a date of manufacture.
It also looks as if your carbine has been through an arsenal rebuild, on account of the bayonet lug and the adjustable sight. Sometimes the stock will bear evidence of which arsenal did the work. Check also for "reimport" marks as most of the carbines floating around today came BACK to the country from places like Korea, Viet Nam and Germany in the late 80's, early 90's