You really need to be posting your request on Dubberz. I bet there are plenty of stock radios kicking around over there. And just in case you don't know, even the basic of Mk3 radios had a security code. Without it the radio is useless. Don't know if the dealers still charge for the code, but they did when I had a Mk3 back in the 90's. The stock VW radios weren't all that great. You would be much better off with a basic aftermarket radio and a wiring adapter. Oh and the stock speakers weren't all that great either so don't expect much.
Actually the factory radios are pretty good, as are the factory speakers, some MK3s even came with Bose sound systems ( i have one like that ) Also some MK3s came with Deluxe radios with Aux In for your Ipod/MP3 Players ( which didnt even exist while these were in production ) I have one like that aswell.
Anyways, just for others information, you dont need the code for the radio, all you have to do is call the dealer with the Radio serial number and ANY MK3 Vin number ( your own works just fine ) and they will supply you the code free of charge.
If they try to charge you, open your owners manual and show them where it clearly says that they provide the code for free.
As far as that radio in the craigslist ad, you dont really want that one because its from a MK4 and will light up red/blue unlike the MK3 which lights up Green. It will however plug right in and work.