Is there any way to see who SecurID tokens were previously assigned to?
The tokens do not have a history that is immediately associated with them - you have to look for this, but assigning a token is an Administrative activity that would be included in an Administrator Activity report.
But keep in mind the AM database is an Authentication database, not really a reporting database, so activity data is archived after a time, to .csv files.
So older administrative activity may not be in this report, you would have to search through archive files. And archive files are also deleted from the AM appliance disk drive after a scheduled time too.
Retrieving data ...