Short answer: most likely.
Long answer: Not every part on a bike is standard across every bike. Think the wheels: Road bikes use either 700c or 27 inch, whereas a mountian bike uses either 26 or 29 inch. This is the same throughout most of the bike. What miyata610 was talking about is the distance between the two rear dropouts (bit where the axle attatches to on the frame), which can vary again. Basically, there are only really 2 absolute standards in biking - and that is the size of the hole the pedal screws into, and the distance between the 2 seat rails (metal tubes on the bottom). Pretty much everything else can differ. Your best bet, like miyata610 said, would be to take it to your local bike shop so they can take a closer look at it.