vintage etched brass tray table w/ solid brass campaign stool base, coffee table size

Large round brass or brass over copper tray with solid brass campaign stool table base. The tray measures 24 1/2" in diameter, and the stool measures 12" in diameter x 14 3/4" tall.

These are not permanently attached together, but were used with museum wax to hold the tray in place. Both pieces are very tarnished, and the tray has discoloration in the center (see pics) which is why we thought it might be copper with brass plating? We have not polished either piece at all, and expect that a good polishing would probably help a lot.