Here is the stock B4 radio in my '97, the part number is 3AO 035 180X. The "X" designates a remanufactured unit, but I don't care, so long as it works. It looks and works like new, so it's just refurbished. It's not a 'great' one, but fits flush in the dash and provides sound, which is enough for me. As I understand it, there was more than one radio available in the B4 platform, but the parts guy at the dealership said the other part numbers yielded no stock left. They are very simple to get out of the dash and change, I did not use the 'special' tools, just a small flat blade to push in the lock mechanism on each side (I did them one at a time).
This is the replacement ordered through the dealership. It's the same radio, but this one has the code on the top. When I put it in, I did not need the code, but have it anyway. It does not come with a manual. It does have the little "VW" emblem on it, but you can't see it from the way I took the pic.
This is the box the radio came in. It also says "Heidelberg CR" on the end of the box, along with all the other numbers shown below.
Here is a picture of the invoice from the dealership showing the price. This radio was bought 2/14/11, so just last month. I also buy the large OEM oil filters through the dealership, which is the other number listed below the radio.
If anyone has a problem getting them, let me know, and I'll go back to my local dealership. There was no shipping on the radio. The parts guy did say there was a limited inventory, so if you're looking for one, don't hesitate. It's why I bought 2.
Many thanks again to Oilhammer, without whom I never would have known about them, and would be either using the OEM radio with no night display or an A3 radio that I didn't really like.