Got for free

[INLAND44]

If the trigger housing turns out to be Inland (big stamp on side) of the right type, you have what I call the 'big 3'; receiver, barrel and housing of the same maker and period, possibly together since manufacture. Even on a rebuild/updated carbine, this counts for something. If the carbine is 'blued' and not Parkerized, it could be original finish although its unlikely. We would have to see good, clear pictures of it. I don't know that I've ever seen a blued carbine with updated features.