[Butch7999]

Rob, we're not so sure that's not a plate. Agreed, it's definitely not period, and can't say for sure without being hands-on with it,
but it reminds us of a flex plate (terminology may vary from printer to printer) for a small duplicator (as opposed to a large press
like for newspapers). In our years in the trade, we occasionally made cheap presentation plaques for framing by just burning
the desired image onto a plate, then cutting away the excess (non-image) area.
Could be completely wrong about Ron's item, just making a guess.

Additional idiotic thought: could "Bros." be an abbreviation not for "Brothers" but for "Brooklyns"?