Permanently Unique Char Names

[hisdad]

Hi,
I'm working on a history addon.
I'm concerned that if the user deletes char "fred" and then creates "fred" that they cannot be distinguished.
Consequently the data for the historic "fred" will be overwritten.

There is a unique name function that merely prepends the server name, which is useless.

Is there some sort of GUID or other permanently unique identifier?
Uniqueness across servers is not required..

Regards,

--Dad