Your choice of school would suggest a Germanic lock, but post-1800, English import locks were so abundant that they can show up on rifles of the York and Lebanon schools.
Another Siler lock would still be a good choice. It's pro is that it has good geometry and works, throwing lots of sparks and making the gun go boom. Its cons are cosmetic--minor appearances of the lock plate, cock, frizzen, and frizzen spring.
In the past, Bud Siler sold only cast parts and not assembled locks. That meant that someone else assembled the lock. That situation has changed. Jim Chambers bought the Siler business and his workers assemble Siler locks for him. Other companies such as RE Davis used to buy castings from Chambers and assemble Siler locks, but they no longer do that. Chambers still sells lock kits, so anybody can still assemble a Siler lock if they want to.
Chambers offers a
Deluxe Siler that has some redesigned parts that improve function and appearance. These include a redesigned cock, frizzen spring, and tumbler.
Chambers also offers a
Golden Age Flintlock that has a different plate than the Siler, but uses the same cock, frizzen spring, and tumbler that's on the Deluxe Siler.
L&R offers the early (1750-1770)
Classic Flintlock. This style lock is suitable for Colonial period rifles.
L&R also offers a
Jacob Dickert Lock that is suitable for a 1760-1800 period rifle.
RE Davis sells
M&G Classic Flintlocks that would work for your build. As I said before, they no longer assemble Siler locks.
The above are all Germanic style locks.
If you wanted to go with an English style lock, your best bet would be a Chambers
Late Ketland Flintlock. It's an excellent performing lock and fits the 1800 +/- period well.
You could go with an L&R
Late English Flintlock or the RE Davis
Late English Flintlock, but in my opinion, these locks are best suited for a later period rifle than you described.
You'll likely get all kinds of opinions and testimonials about quality and problems with some of these locks. Chambers seems to be the most highly respected and praised locks today. So much so that he has raised his prices well above those of L&R and RE Davis. Whatever the market will bear. L&R has had a long history of changing owners since it first started up in the 1970s, and some of those owners seemed to let quality controls slip. The present owners seem to be doing better. RE Davis makes good locks. The internals may not be finished as well as most Chambers locks, but they are functional and reliable.
For comparison, the 2018 flintlock prices for the three makers I mentioned are:
Chambers $195
L&R $170
RE Davis $160
Prices for 2019 are likely to be higher.