well, the best i can tell you is to locate the serial number, it should be stamped on the bottom of the bottom bracket shell. from there, you may be able to locate a site that will give you a date according to the sn, or you could probably email or call specialized with the number, they should be able to tell you when your bike was made.
by the way, you got yourself an awesome bike that will ride great. i have always kept my eyes open for an older hardrock or rockhopper for cheap to have as a backup trail bike.