It sounds like you've already read the part description on the faceplate. With some google searching you should be able turn those into part numbers. For example, the 7500 route processors should say something like "Route Switch Processor 16". That particular part number would translate to RSP16. The fast serial interface part number is either CX-FSIP8 or CX-FSIP4 depending on how many ports it has.
The 5k parts usually (but not always) have a part number printed in the upper left hand corner of the cards faceplate. They usually start with WS-.
