For dating the model – paint, dropouts, head tube, cabling…
http://www.vintage-trek.com/trek-fisher ... emond.htms
Re xtr – FC-M900 110/74BCD is square taper.
FC-M95X odd BCD, could be cured with aftermarket spiders, takes octalink V1 112.5, or 116 (BB-M950 rebuildable, BB-M952).
Some folks...