Well done on finding the kilt pin. I don't want to get your hopes up, but, it might be silver and it might have been made in the UK, in which case there is a good chance there will be Hall Marks on it. Other countries have Hall Marks too, but in the UK you would be able to see who the maker was, a date letter, usually,but not always, where it was made.You may need a strong magnifying glass.Good luck.