Craig,
A lot of this stuff was very good quality, and made for the VEIC. (East India Company)
Such guns were made in the UK and inspected at every stage , and bear London proofs.
When you mention some "old army disarmed" you are pretty near the mark!
Towards the end of the Indian Mutiny, many mutineers fled up into Nepal, and were there disarmed but otherwise not detained by those allied to Britain.
These arms were inventoried and used by Nepal. Such is the case for most of the EIC percussion musket models.
These muskets have a Very interesting history, and are usually still serviceable.
They are marked , often by known inspectors, and are date coded so we know what year each part was made. As time permits, I will show you one of mine.
Must add, that not All arms from the Old Palace are British;
Some are all Nepalese made and not quite up to snuff, but as these are mostly of certain types, there is little confusion as to which is which.