No it's separate - this is something that they don't really explain until you get there for orientation.
You only need your UB person number if you want to get a parking pass and access to the computer stuff (e-mail, etc) before orientation. I think you can show up at the UB Card office with your SS# and some ID to get your UB ID which has your person #, and then for computer access you go to the computer store on North Campus which has a terminal set up for getting your password.
But like I said you don't really need any of that before orientation; during orientation there's time scheduled out for you to go handle all that stuff if I remember correctly.