if it's an Ed30 then it'll have had them from the factory.
if it's a standard car my guess is they're reps, but the only way to tell is to check the back of the wheel. it should have VW stamps along with the size and BBS stamps.
08 cars are fairly new, but if it's strayed over 60k miles (or approaching) then it'll need a cambelt/water pump change. make sure this is done. it's expensive!
other than that they're pretty good. just check the standard sort of stuff. surprised it's rusting already? i'd see if the owner can get this sorted from VW before cash exchanges hands.
lowering wise it depends all on budget. i got some 2nd hand Weitic Hicon GTs with 3k miles on for £400, and then £275 to fit with a full laser alignment. i didn't need the adjustability, it was just so i could get it sitting exactly how i wanted. i'd recommend them all day