As
@BPeter mentioned, that's the general part number, but a lot of them on ebay seem to have the wrong part number listed and/or not at all, so I'd tend to search for 'model 3 clockspring' or 'model 3 turn signal' or similar. That's how I found five for less than the cost of one new one from Tesla.
I did get the shifter to work, thanks to the fact that the phone dock's backup system for shifting can send appropriate signals, which I just duplicate.
I was able to get all five of these for almost nothing and have a few friends who I'm sure will want them, so just got them while cheap. I still have no plans to sell or support this at all. I also now have many tries to mess up, I guess.