Nice bike
There's an article about the 1997 monster here which gives an indication of standard spec for that year. My guess is someone has raided a later S4 or 900 for parts (Forks, brakes, wheels, mudguard, indicators, teatray etc..) to up-grade the 750, with the chromo tank also coming from a later spec 900. The give away is the slight miss-match on seat to tank fitting. Earlier seats & tanks have a different shape both there, and at the knee cut-outs, which has led to the slight gap at seat on yours.
http://www.motorcycle.com/manufactur...ter-14353.html
Anyway, enjoy your new purchase and welcome to the UKMOC family