Digging into Ruth's book, you see Inland going to Ordnance and getting permission to use rejected barrels that will work. Guaranteed that the bin was down to the bottom. My 5.4 has a 8/44 new barrel that has rifling like a 45 automatic, shallow as hell but it would work. The barrels were always the problem and the cause of production issues. Look at NPM...they were using anything they could get and IBM gives them thousands of new hi quality barrels at the end of their run. Please look into Chris Albright's articles they go through the carbines part by part and you'll see what you've got.
I'm just not a great fan of Inlands. The finish is some odd black stuff that scrapes off mine when you move the band back and forth. The top HI handguard is new and yet you only see about half of the front sight when aiming. You just wouldn't see this kind of stuff on a Winchester or NPM. You can tell that Inland made good car parts.