Hi,
The lock is a Davis "Tulle". I hate that big ugly notch cut in for the flint cock. There is no need for if you know how to shape the stock correctly. That said, the TOO big flint cock on these Davis locks need a lot of clearance. I appears to be made by someone who is competent but whose knowledge of French trade guns comes from the Track of the Wolf catalog. I have not seen an original example with a side plate like that. All of the ones I've seen were solid with no piercings. However, TOW sells the plate as a "Tulle" component so maybe they have some reference for it.
dave