You have a "Base" model. Only base models were made from 1997-1999. In 2000, Porsche introduced the "S" model to sell along with the base model. The S had a bigger engine, larger brakes, and a few nicer interior bits than the Base.
Here is how to decode the label under the front trunk:
And here is the list of options:
http://www.964uk.com/Documents/Porsche%20Option%20Codes.pdf
Match the factory option codes listed on the label under your front trunk with the list of options from the link above, and bingo, that is what came with your car when purchased from the dealer.