To make my front hubs greasable, I replaced the bolt that holds the ABS sendsor in place with a grease fitting, after I drilled down thru the bolt hole and into the cavity between the inner and outer bearing with a drill bit . ( of course the drill bit must be small enough not to damage the threads,and you don't want to let shaving get into the hub or damage the tone wheel inside the hub)
I got 95,000mile out of the OE hub on the left side and when I replaced it I added the grease fitting to the new part and did the right side as well. The right side is still the OE part, with 195,000 miles on it. The dealer told me that this part typically last only about 75,000miles. I got stuborn and figured I'd outsmart DC and make it last much longer. So far so good.
I have been greasing the hubs only as often as I have a reason to remove the rotors.
I guess you could make it greasable without removing the rotor, but greasing the hub as often as you replace front pads seems to work fine.
Good luck, I think you'll be happy to save the price of a few hubs over the life of your truck.
Rick