Hi
If you are installing non-cisco GBIC then you can see the error logs in your logs if you have already enabled logging in your switch.
you need to configure it using hidden command
"service unsupported-transceiver"
Stack1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Stack1(config)#service unsupported-transceiver
Warning: When Cisco determines that a fault or defect can be traced to
the use of third-party transceivers installed by a customer or reseller,
then, at Cisco's discretion, Cisco may withhold support under warranty or
a Cisco support program. In the course of providing support for a Cisco
networking product Cisco may require that the end user install Cisco
transceivers if Cisco determines that removing third-party parts will
assist Cisco in diagnosing the cause of a support issue
regds
