By original I do mean GI but also as issued. Almost all M1 Carbines came with flip up rear sights, no bayonet lugs, and flat bolts (not round).
Late 1944 all 1945 Inland, Winchesters Carbines had the later features.
Adjustable rear sights, bayonet lugs, and round bolts. A couple of others started to use late features like Rock-ola.