Those GM retailers are just resellers not officially GM dealers.

 

19301489 is for cars with active brake control. Does your passenger side glovebox door RPO sticker show JL4?

 

Universal or not the EBCM needs programming.

 

Update to the situation. The module quoted above is for the SS, which I bought since I did the four wheel disc conversion. However, that module has to be able to communicate with the electronics module it's plugged in to, and that module also has to be "SS" related. Since I bought an SS modulator and an LT/LS control module, neither one worked since neither one could be programmed to talk to each other. So, control module 20827127 and modulator valve 19301486 were ordered. And everything seems to be copacetic at the moment. Brakes are perfect.. snow is on the ground now, so I'm sure I'll see how the ABS works here in a day or two.