Rich,
Thanks for your interest. Here is a photo of the lock, reconverted from percussion back to flint.
Here are some dimensions of the gun:
English Trade Gun
LOA 52.25 LOP 13.25
Barrel LOA 37.18 Breech 1.22 Muzzle 0.72 Bore 0.56 Marked LONDON plus English proofs
Buttplate H 4.75 W 1.75
Lockplate H 1.18 L 6.25
Rear ramrod pipe to middle ramrod pipe 11.25 (this is the length of visible ramrod)
Middle ramrod pipe to front ramrod pipe 7.25 (this is the length of visible ramrod)
The gun was shortened at the muzzle sometime during its useful life and the front RR thimble replaced with a simple copper thimble.
Let me know if you wish more photos.
Jim