OK, Here goes; first place, TCs are not the cookie cutter duplicates one my think, they vary a good bit, not all but some.
I had a TC percussion Renegade stock and a flint barrel and decided to make a flint Renegade with an L&R RPL lock. I bought the lock,the first one had a casting flaw in the nose of the lock plate so it went back, the second one had a incorrectly fitted tumbler shaft. The cock only hit the edge of the lock plate at the cock stop so it went back. When it came back they had reground the shaft but forced it through the lock plate burr and all, the tumbler wouldn't even rotate. I knocked the tumbler out of the lock plate, filed off the burr, polished everything up an moved on. (no more L&R locks for me)
The L&R wasn't close to fitting the mortise, I had made two plank builds and a precarve before I attempted this so I wasn't a rookie. First, the barrel touchhole and the pan center were 1/4" off, I moved the barrel and tang back to center things up, this required cutting some of the under rib off, the TC lock bolt didn't come close to hitting the fixture on the L&R bridal so I plugged the old hole and drilled a new one, I figured out a way to drill a blind hole and actually hit the tiny socket on the bridal.
Well, the lock bolt was now hitting the back of the barrel so I ground that off to get bolt clearance.
The L&R lockplate was smaller than the TC inlet so I had to glue in shims to fill the gap.
Of course I had to do a complete lock inlet job to accommodate the L&R internals, no big deal as I had done the same a bunch of times before.
The first picture is before I blued everything, you can see the offset lock bolt hole and where I ground the back of the barrel off to let the bolt pass by.
The second picture is the finished gun with a few shims glued in at the tail of the lock. The lock sparks well, I sold the gun to a guy who will never shoot it so it is an unfired gun safe queen.
Some people who use the L&R RPL locks run into some of the same things I did, for some it goes relatively easily, your mileage may vary.