So here's the update, the GM 19420494 is the OE part and is a Z55 cartridge. Found one at a dealer and the parts manager put his hands on it and verified one of the #'s I have on mine, 22273763, also has the provision on the top for the sensor.
I looked at GM Parts and the price is good, but shipping is brutal...lol. $127 to ship 2 shocks 1 state away....
I looked at GM Parts and the price is good, but shipping is brutal...lol. $127 to ship 2 shocks 1 state away....