[Rick the Librarian2]

There are a number of points to look for - can you post pictures?

 

[Rick the Librarian2]

If the serial number is correct, I doubt it is a NRA Sporter. Most of the 1290000 range receivers were those gotten from Rock Island as "blanks" and I believe they were made into service rifles. I'll check with a friend, though.

Some of the other characteristics would be a Star Gauge barrel (a "star" in the 6 o'clock position of the muzzle crown) and a star gauge number (like B4557) on the top of the barrel towards the receiver end. Also, the bolt should be marked lightly with the serial number on the bolt body.

 

[Rick the Librarian2]

Interesting! Michael is the "real deal" and if he says it's an NRA Sporter, it is.