Hi Matt and welcome to the Forum. This, (from what can be seen) is a typical piece from the general area---Khyber Pass/Afghanistan. The lock looks to be definately genuine and is from a British India Pattern musket. It bears the correct date and the British East India Company heart shaped cypher. Also also has the name of the (private) maker. If you can tell me what that name is (not clear in pic) I can probably give you some dates as to when he was in business. The barrel LOOKS old, though it may not NECESSARILY be the one which went with the lock originally. (Barrel length?) Any markings of any sort that you can see? Also replacement bits like bands are quite common on this type of firearm,but also COULD have been added recently to make things "look more attractive" for the buyer. More pics would be great including a full length.
Keep safe.
Regards Stuart