Extremely heavy duty, thick gauge steel with rivet construction. No markings on it that I can find but my father served in the Marines and His opinion is that it is definitely military issue.

To me the numbers look like it may have been used on a naval ship because of the font, and how heavy duty/ galvanized it is. (2 lbs 12oz.)

The number possibly corresponded with an aircraft number for a flight log/maintenance log? Obviously I can’t say for certain it was, but I can say it looks the part and I can’t find another one like it.

Definitely a unique and awesome piece.