I bought a polished aluminum Gary Fisher Mt. Tam with Deore XT components, Deore LX crank, and Manitou (X-vert E) front shock at a Yard Sale. The Mt. Tam has purple decals. Does anyone know how I can determine the age of the bike? Is the Mt. Tam considered a step up or a step down when compared with the Gary Fisher Big Sur. Thanks for any help you can give.