Is that box supposed to belong to that gun? If so, I agree with Wetdog's first sentence.
His third sentence has me a little puzzled, though.
Should there NOT BE writing? Should the writing be PRINTING instead of cursive? Should the writing be PENCIL instead of ink?
Or is it the phrasing. If it had been written at the factory, where one would assume it was written, why would it say "Early Production", and why say "5 screw" unless they could see in the future and know they would also make 4 screw and 3 screw?
Reminds me of a sword I read of one time. Engraved that it was presented to Stonewall Jackson after the First Battle of Bull Run. If they had not had the SECOND battle yet, how did they know that was the FIRST battle. And it was the Battle of Manassas, anyway.