Hey Tom,
That's more than speculation, this shotgun has a history. The Real Deal.
Shipped the same week as Pearl Harbor.
To think, someone, almost 80 years ago, noted down this little factoid in a ledger.
It was used a few times for accounting and such, maybe. Until Now.
It becomes The useful fact to identify A shotgun in That shipment.
This shotgun Is history. I'll just admire it all the more. Chopped up as it may be. It's a Hella Shotgun!

Some Questions:
easy one first;

What was the original butt plate like?

Did Roy L. Brolin stamp it before it left Ithaca ?

Was the UNITED STATES PROPERTY stamped at Springfield Armory?

Are there any other known shotguns in this lot stamped with UNITED STATES PROPERTY ?
ie: Is the shotgun that scosgt owns, in this lot as well?

Are all 200 separate serial Numbers listed in the record for Dec. 12, 1941?

What did Springfield Armory do with the 200 sporting shotguns?

Well, thats enough for now.
If I think of any more, I'll keep 'em to myself. for now.
What reference book would you recommend.?
Thanks,
Stay Well.
jm