date of last backup on the media

I have a stack of tapes LTOs that I believe are month ends.  I did an inventory of the media/LTO Tape and the dates I see IE allocated Date, creation date modified do not seem to match what I believe this tape to be IE I say this Tape is July 2012 end of month (last used) and those dates are Creation date 11/11/2011 Allocated date 11/30/2011 and modified date 12/1/2011.

So with me thinking this is July 2012’s end of month this doesn’t make any sense.

Yes I have inventoried and cataloged but I can’t seem to find the date that I am looking for. The date I need is the date last used, the last time this tape was used as a backup.

Symantec Backup exec 2010

thx!!