Hi Raymond,
I agree that it is likely a jezail. The art work suggests Muslim to me rather than Hindi. I've handled 3 jezails over the last decade and yours is the first matchlock version I've seen. Most surviving jezails seem to have British musket flintlocks, which is not surprising. I suspect surviving matchlock versions are earlier and more rare. Be careful looking for images of jezails on the internet. There are a lot shown labeled "jezail" that are nothing of the sort including Albanian and Balkan guns with Mediterranean locks. It seems to some, every gun that does not look European or American is a "jezail".
dave