Like Shamus said, it's mid-90s frame. The seller got it all wrong in his ad, probably tried to make it look more desirable?
The XLM was introduced for the 1995 model year and it had a canti stop in the rear for 95 and 96. It has the same geometry as the Mountain model but has thinner (butted) tubes. I've heard that those tubes are prone to dents so be careful.
I wouldn't use a 80mm fork on it, probably makes it too "choppery". If you already have some surplus fork, it doesn't hurt trying it though.
I'd use a rigid or something like Pace, Judy SL, Manitou 4/Mach 5 or