I've had a particular Stickies' note around for several years (a nested a keyboard character for easy access).
I'm not sure, but the Stickies' notes seem to be maintained in the "StickiesDatabase" file found in ~/Users/Library folder. ...I have 2 Macs, and both of the Stickies db files are present and with the same keyboard character in both notes.
This seems to confirm particular notes have been carried forward through all OS Updates, including 10.8.1, for the last several years as I've had both Macs since mid-2010.