OK, I went back to the JY this morning with my dad. While he was getting stuff for his car, I ran back to take a look at the Bonnie I got the button from. There were a lot of parts missing so I got a clear look at the ABS unit. It had a sticker on it that said "ABS-5/TCS/Blah/Blah". TCS meaning Traction Control System, I assume. We didn't have time to pull the module but I'm going to have a look at mine later and see if, by chance, it already has a TCS module in it.
1999 Grand Prix GT