I've put in a couple of those in the past. Neither was a direct drop in to the TC lock mortise but they are very simple to install. A little, and I mean only a little, work on the tight spots in mortise with an exacto knife or small chisel will allow the lock to set right in. Of course this makes for some very small gaps around other places in the mortise. If that bothers you, you can fix that with a little bedding compound tinted to match the TC wood color. It makes a very nice improvement over the TC flintlock.
L&R Locks are well made locks and their service is good. I had a frizzen spring break on one of mine the day before leaving for a hunt. I called them and they sent a new one to me that UPS delivered to me at the hunt camp the day I arrived.