Hello Pollup;
I do have an 01' TT 225 HP and it chipped and since I am the first owner I know what it has. Unfortunately, there is no real way to check unless you have the chip removed and inspected (serial # etc). Since there are so many chips out there it's hard to tell how to check. One suggestion would be is to go to this website
APR - Engineered Performance for Audi, Volkswagen, and Porsche Vehicles and see their chip features and functions. If your car has the same processing and change features then 'bingo' you know you have that particular chip. If not, it don't necessary mean that you don't have a chip, just not that one.
In terms of maintenance, since it's a second hand car and if you don't have the full service history, your best bet is to take it to a dealer or to a reputable sport/mechanic shop for a check up.
Hope this helps