Mine has a guard/bracket that covers the bottom and sides of the lower U-joint. It was put on as part of a recall that included new heat-shields and new muffler.
On the left side of that bracket (as you are sitting in the operator's seat) there is a roughly 3/4" hole. If I rotate the driveshaft to the "correct" point, the grease-fitting on that lower U-joint lines-up with that hole and I am able to use an ordinary straight grease-gun to grease it. The hole is located in such a position that the U-joint yolk is opened up and the grease gun fits on the zerk fitting perfectly and without interference.
My mower is sitting in the garage right now waiting for the temperature to cool down some so that I can grease it and put new blades on. I will take a pic while I am greasing it and post it here.
If it matters, I have the 72" deck and the 35HP liquid-cooled Briggs engine.