Thank you degoins.

The sight on my Flintlock is made up and finished from a casting, from Allan Foundry.
You have to put them together, but it's not all that hard to do. They are not a standard 3/8, They are a bit smaller and shallower. You have to file them sharp before you use them, so the dovetail will vary in size depending on how much you file it. You can buy them from Track of the Wolf.

The sights on the English guns were all hand made, so they can't be bought. Each one was made to fit each gun.