Actually you do not need to pull the drive shaft assembly all apart and grease all the splines on a VStar 650 everytime you change the rear tire.
Some of the early bikes were not properly greased at the factory, or they used the wrong grease, and the splines failed.
There is nothing in the maintenance schedule for the bike on greasing the drive shaft. That is the whole point of having a drive shaft instead of a chain, there is very little maintenance.
It certainly does not hurt to clear off the spline that is exposed when you change the tire and put new grease on it, or to disassemble the rear drive and grease the other 3 or 4 in there, maybe every 30,000 miles, as long as you use the right moly and do it correctly.