The maker is likely Thomas Spencer who was active at least from 1819 to 1841. The lock is signed "Spencer" in script and has some light engraving. The barrel has "LONDON" on top, London proofs on the upper left, and an 11 inch folding bayonet with a release on the upper tang. The muzzle flares to 1 1/4 inches and has an approximately 16 gauge bore. The furniture is lightly engraved brass.

Very good plus overall with attractive natural aged patina on the brass, mottled gray patina and minor oxidation on the lock, a crack in the wrist, repair by the nose of the lock, minor handling and storage marks, and distinct engraving and markings. The bayonet system and lock both are mechanically fine.