Zaxxon,
Try this, go out to solarwinds.net and download one of their professional suites (at least the one with "IP Network Browser in it) Install it and open the program.
Before you can do this you need to have SNMP enabled on the 2900. Plug in the information to scan a single host and under the CARDS tab it should list all the serial numbers of the cards.....
Let me know if this works for you, it works for all my Cisco Equipment that I have, hopefully it will do the same for you.....
david e
*end users are just like computers, some you can work with...others just need a simple reBOOTing to fix their problems.*