My thoughts ...
BARREL - The barrel appears to be real and the proofs appear to date to the Birmingham Proof House ... but of 1904 to 1905?
That I don't get, because I could be mistakenly reading 'smokeless powder' proofs, and yet, the chart does go back to 1813.
LOCK - To me, the English would have some name like 'Tower' or other on the lock. And now thart I think of it, I don't think I've ever seen an UNmarked English lock, haha! It looks either French or Belgian to me and the sideplate looks Belgian to me too ... but I'm no expert. But I do see a maker's mark or some mark at the top of the cock right above the top jaw? Can you read that? FWIW I've never seen anything like that on an import lock made in India and it does not look like a lock made there, to me anyways.
Note the Belgian martial arms industry was extremely prolific in making up arms from parts from scores to 100s of years old, even as of 50-60 years ago they were still making flintlocks and selling to tribes in Africa who were banned from owning modern arms!
STOCK - Can't really see enough to judge, but haven't seen a band like that on an Indian import. It could be someone bought a bunch of parts and made their own?
In regards to British arms, the resident expert on here is Dave Person (username of dave_person). So if he doesn't respond here, maybe you could PM him and ask his advice.
View attachment 254597