Quick question that I searched found no discussion....

I'm cleaning and flushing all systems on my '07 NBS Sierra including the front driveline and in doing so I removed the plastic actuator unit from the the differential (see photo). It appeared to have a white dope on the threads similar in consistency and color to home plumbing pipe thread paste. After cleaning and before re-installing what should I apply on those threads? Anyone have any clue what the OEM call-out is on that item? I'm a maintenance mechanic by trade so I understand basic sealing processes but I'm curious as to what if anything others have used in this area and what GM does at the factory - can find nothing online. Thanks in advance!