You'd have to post more pictures because from that one angle it looks like the hammer goes to nowhere, and if that is the case then you have a fake, reproduction, toy, or prop. Also the screw on the hammer looks to be quite small, possibly a rivet. All the antiques I've seen the screw is very sizable and easily seen.
More over the lack of any wear on the caplock begs to question its actual age.
Here is a few images of what actual antiques locks look like: