The splines on the front of the driveshaft use EP Moly grease.
Unless there was a problem or issue in this area, I have no idea why your guy pulled the driveshaft assembly and even touched this area?
My only concern would be if he didn't seat the rubber seal correctly in the U-Joint area, or caused a leak around the transmission shaft (just keep an eye out for oil leaks in this area)
I would NOT pull the shaft just to check his work, as there is not much he could have done to damage anything in there, and if he used EP grease, your good.
I would make sure he torqued the 4 nuts on the driveshaft housing correctly, as most mechanics just use a box end wrench, and you don't want that coming apart on your vacation.
If you want to do your wheel CORRECTLY, clean and apply the paste on both the MALE splines (on hub of wheel) and the FEMALE splines (inside the housing)
And while you have your rear wheel off, and sitting on the ground, you'll notice there is a very large C clip around the perimeter of the hub. Remove this clip, and lift the spline assembly off the wheel, and clean this area, and apply the paste as seen in the pictures I provided.
When you replace the clip, make sure the SHARP edge is facing outward. You can identify this by looking at the end cut of the clip, the sharper edge will be longer than the rounded edge.