@Koltin As far as I know all pre-DTRE master cylinders are the same from 1988 until around 2004 so I'd start by comparing part numbers on Fowlers website, look up the part for say an '88, a '96 and your own bike:
https://www.fowlersparts.co.uk/?gad_source=1&gclid=CjwKCAjwl6-3BhBWEiwApN6_ks8FnxkMK8pUTlwAmDTt4wZ4GV5FlSqAj_zeubTOZF-qK69xd1CwVxoCpO4QAvD_BwE