If the bearings are open face, yes.
If the bearings have a plastic or metal cover over the balls of the bearing, not unless you want to try and get the protective cover off of the bearing.
There will be a metal piece over the bearing with what is called a slinger, it kind of runs in grease and is there to keep water out of the bearings.
By the way, if it helps, if you go to Rainvac's web page you can download a schematic for the D/D2.