I had to smile at first, because it looks to be the same pistol kit we got dad for xmas back about 77. I still have it. Have you tried contacting CVA for the lock?
My thoughts on getting the L&R lock...
about two months ago I ordered one for my Great Plains Rifle, understanding that it needed minor fitting. Wrong. Dead wrong. It required major inletting , and when I got about 1/2 way through it, I realized when done that the hammer wasnt even going to line up appropriately, and the fit to the previous opening was very poor. Double underline.
Luckily I was at the stage that I hadnt done irrepareable damage to the gun, and I called it quits. TOTW took it back with no problems. The old lock will go back on.
I would try to find the actual lock, if this is your first effort. Have a bit of patience, you can probably find a used pistol for a good price to steel the lock from. Checking the local on line auctions, and several previously on GB, avg. prices were only about 50 bucks a year ago. Granted, who knows now, but BP firearm prices are not affected as badly as centerfire.