The change to disc brakes was '01 I believe. Otherwise the kick start was also replaced in the mid 90's I think. You're better off keeping that. The brakes is really the only advantage that I can think of. You can at least get front disc brakes with a new front end, a rear drum will be pretty well okay I'd think.
You have the option of using different forks and wheel at this point. I think it's the xt225 that can be used. Not positive though.