May have answered this myself... Looks like mine could have been reused without issue. I'll check the connection.
"If your brake sensors activated the lamp on your dashboard, they should be replaced with new ones. Disconnect the sensor (Figure 14), and plug in the new one. Then snap the new sensor into the small gap in the brake pad (Figure 15)."
"Rick Comments: I have a 2008 528xi with 31,000 miles. The brake light sensor has not gone off yet but I am replacing all the pads anyway. Do I have to replace the sensors when I do the pads?
April 5, 2011
Followup from the Pelican Staff: If the light has not gone off, then you probably don't need to replace the sensors. I would take a close look at them when you remove them from the pads - make sure that they have not started to wear at all, and are like new. If yes, then simply reinstall them into the new pads - don't even unplug them, as that can sometimes cause issues if the plugs don't seat properly. - Wayne at Pelican Parts"