I went and did some research and found the old thread where I originally learned about doing this. The info given there was too use a non-moly, lithium grease. I "think" I have Mystik JT-6 high temp grease in my gun, since those bearings are probably the last thing I remember lubing.
My F350 had ~100k miles on it when the front bearings both failed within about a thousand miles of each other. I started greasing them once a year after that and it had ~215k(?) miles when my ex-wife took it. Bearings were still going strong. The Ford forms have a lot of people who have had significantly improved bearing life after adding grease.
Of course, being new to Ram, I can't vouch for applicability to these trucks yet, so.... You have been warned!