I'm sure it's possible to reuse a head gasket, but I'd never do it. I've got too much time/money into my bike to do that.
Certain types of metal gaskets can be reused. Copper head gaskets are one of these types. I've seen drag racers reuse copper head gasktes, but they had o-rings in the block/heads.
Locating a gasket shouldn't be too hard, especially if it's an 88+ motor. If it's an 87 or older,
www.cheapcycleparts.com has the gasket kit in stock. I know this because I order on last night. All the other major online compines (DennisKirk, BikeBandit, Motosport, RockyMountain, ThumperTalk) were all on back order or would have to wait 2-3 days before shipping.