First thing - Pop your front trunk. Look for a piece of white paper glued near the latch with a bunch of numbers and letters. Those are the build info and options for your car. Hopefully - the dealer hand wrote the radio code on this option list. Look at this link to Pedro's option code list and you'll see what I mean.
Porsche Option Codes List
If it's there, yay! If not?
The fastest way is have one of the eBay guys send you the code for a whopping $4.99
https://www.ebay.com/itm/293240556545?hash=item44467fcc01:g:Sk4AAOSwwOtdhSD z
Also - if it's not handwritten under the front trunk, dig through your owners and service manuals that hopefully came with the car. I've found it there before too. Either handwritten on something, or you'll get lucky and find the original card with the code.