I'd say if you go through the whole process of getting hired again (all that computer work) minus the orientation you can consider yourself "rehired."
It's possible, despite what some people here want to tell you. It's just a small portion of the seasonals overall are kept, and even then they usually [read: not always] get the call several weeks to several months after peak ends due to the sudden drop in volume at the start of every year. Also, UPS kinda has a thing for dickin' around it's employees-- seasonals especially. A lot of the people here recognize that and are pretty brutal in how they go about relaying that info to new users.