Use this undocumented, unsuggested cli command to get sfp bays inserted media serial numbers

 debug fastpath cfgtool --dump.sfp

(WLCTS 5508) >debug fastpath cfgtool --dump.sfp

(WLCTS 5508) debug>FP0.
Port SFP Vendor       Transceiver Type    OUI PartNumber       Rev  SerialNumber     DateCode Auth
   1 CISCO-METHODE    (0x08)1000BaseTX        SP7041           E    00000MTC655363SA 08127501 ok     
   2 CISCO-METHODE    (0x08)1000BaseTX        SP7041           E    00000MTC655356KS 08127501 ok     
   3 Not Present      (0x00)NOT_SUPPORTED                                                     fail   
   4 Not Present      (0x00)NOT_SUPPORTED                                                     fail   
   5 Not Present      (0x00)NOT_SUPPORTED                                                     fail   
   6 Not Present      (0x00)NOT_SUPPORTED                                                     fail   
   7 Not Present      (0x00)NOT_SUPPORTED                                                     fail   
   8 Not Present      (0x00)NOT_SUPPORTED                                                     fail   
FP0.