What name is engraved on the rib of the barrels? To confirm they are Alex Henry make a call to Dickson & Sons to get a description to confirm with the serial numbers. The back action doesn't appear to be an AH. Although AH rifling was common for many makers.
Neither of these 'crank' locks, which is good for restoration cost.
The bar lock AH has a rather late serial number, I have a .360 falling block close to this number and it was made in 1901!
My uncle Bill Roberts (deceased 2004) build a few AH bar locks and they were in line with Brazier quality for no less than $1000 each in the white 10+ years ago. My guess to get one top lock today will run a little more. PLUS you need hammers!!!
Interesting that the AH bar lock rifle have no engraving, even seem to have border line engraving.
Jim (long time friend of mine) and Steve can certainly do the work, reach out to them. Another avenue may be Bob Roller in W.Va. He builds locks and I know he has a small pattern bar lock off a baby Whitworth. Then again, the internals of his lock may not fit the inletting of your rifle? I don't know if he'll be interested in fitting the lock to the gun. If so, he could make the lockplate oversize.