Yes, Fake and Bl***y awful at that.
To add to Dave, and to not give too much away to would -be fakers, that trigger is of a type never seen on an anything, never mind a Brown Bess.
That "engraving using a vibrating pencil, or Dremel as Dave says, is as bad as it comes.
Monty,
Maybe let the auction -site know, (May be they do know already, but need a prompt!)