I am trying to determine the age (and potential value) of a neighbour's Specialized HardRock Mountain bike. I am guessing late 90's but am not totally sure. It has cantilever brakes, 21 speed, Altus derailleur, Twist style indexed shifters, a rather plump padded seat. This is a Canadian bike -- not sure if they are different than American models. Anyone hazard a guess or can point me to online resource to help me?