I like it a lot. I might change the front nose of the lock plate however. The sharp corner in the wood may give some stress points and invite some cracking but more to the point, it doesn't fit with the curve of the panel that the lock is set into. So, I'ld round it off with a radius as much like the top rear of the lock as possible (scaled down of course).
In a Hawken, the forward edge of the lock plate would come forward to meet the back of the breech plug on a slant. While you wouldn't want to do that here because the latch is not immobile, perhaps the lock plate would be made to come forward a bit and follow that same angle as the lock. There seems to be lot of space there.
Would recoil put pressure on the latch if you fit things tight? In 2 dimensions, I can't tell what is going on there, but I would think that might be an issue. The latch should be VERY free of recoil pressures so it does open unexpectedly or become damaged in some way. Perhaps that is all a nonissue; I don't know trapdoors well enough.
But overall, it is beautiful for sure. If only one could get a rod in the back of a trapdoor - I could be tempted.
Brent