Yes, I light coat of chassis grease or
oil on both surfaces. With a fixed differential the driveshaft yoke doesn't slide any appreciable amount in and out when the car is driven but a little lubricant can't hurt installation. Once in operation a little tranny lube probably makes it's way in there over time to keep it lubricated. A thin coat of grease on the outside of the yoke helps protect the seal as the yoke is inserted.