M1 Carbines come all different ways so configuration is more a case of 'next part out of the bin.' For instance, I have a '43 National Postal Meter that went through a Rock River Arsenal rebuilt (RRA stamped on the stock and the box I got it in 39 years ago for $80) but it's still got a high wood stock, 2 rivet handguard, and doesn't have a bayonet stud. I don't know how that got by inspection but since I got it from RRA stock in their box, I guess some did.
I pulled the carbine out of the box all those years ago and it looked new so I thought it must have been repark'd, however, the Marlin barrel (correct for NPM) gauged at less than 1 at the muzzle (unfired) indicating it possibly was issued but didn't see any use before it was updated. I found out that they just pumped out the rebuilds with whatever parts they had at the time, hence the lack of a bayo lug but all the other updates (Type II sight, lever safety, etc).
