There is also a fitting on top of the idler pulley bracket at the pivot point.
When greasing the spindle bearings there is a weep hole in the center of the housing. I have an air operated grease gun and pumped a few oz of grease out this hole while watching for it to come out the top or bottom on the first one.
It is best to remove the deck and turn over to grease. It's tricky to get the belt back on. There is a square hole in the idler bracket that a 3/8" ratchet/breaker bar fits in so you can pull the pulley back to put the belt back on. You just have to stand on your head to do this!