RD53 Disk Not Rotating

I hope I haven't made a mistake here. Rather than go to Farnell where I need a minimum order amount, I looked on Ebay and found someone with some TIP125s there. I had assumed they were all the same and just chose this one: http://www.ebay.co.uk/itm/TIP125-Transistor-/290672643190? pt=LH_DefaultDomai n_3&hash=item43ad708c76. I haven't spent a lot, so if I have bought the wrong thing it is no big deal to go and find the right ones instead. On the original the only other marking (apart from a TI logo) is "8702", but my web searches don't seem to indicate that this means anything. The Ebay one has no other markings to help me distinguish anything either. So, I don't know if I have bought the wrong thing or not. Are they all likely to be similar enough not to matter? Or should I be looking for a closer match? Not that I know what a closer match would be.