Do they have grease zerks? If so, then of course lubricate them. If not, there is no way to lubricate them and the are not designed to be lubricated.
Grease zerks are usually located on top of the deck, on the side of the spindle, or on top of the spindle, or on the bottom of the spindle (on the underside of the deck).
I'm not sure about your model, if it has zerks, maybe someone would know.
you still can put grease in them if they dont have grease zerks you simply take the belt off take the blade and top pulley pull the deck spindel out and pop the shaft out and grease them up real good if they have no lubercation they will eventually wear.
most all the murray bearings are sealed ( they have two seals one on each side of the bearing ) i always clean the housings and pop out the seals on one side of the bearing and put grease in the housing put the bearings back in with the open part of the bearing towards the inside