The barrel markings may be from a 1966 Springfield Armory 7.62 mm conversion ----- or not. We know where the markings are, & we know what they look like; if you post photos, we may be able to tell you more.

I'd try to get over the attraction. It still has most of the bad features of the M1 rifle: it's too long, too heavy, & it lacks the light recoil of the M14icon-clones.