Leave it. If there is excessive vibration at 60 there is probably something else going on. None of my live-axle rigs have had excessive vibration up front even at 70-80mph.
My 98 Ranger had the autohubs and they were terrible. I replaced them with AVM manual hubs and they worked okay for me, better than the auto hubs. A lot of people had them fall off or shear off. They are cheap, but they basically just snap on because of the design. The live axles are far stronger, less to fail, and you're probably not even losing 1mpg with them versus running unlocked.
Really the only advantage to swapping to AVM hubs is that if you break a CV joint, you can unlock the hubs and keep driving. That isn't an issue for most people.
2006 F150 FX4 Super Crew - Bilstien 5100s leveled 2", 35" KM2s, 4.56 gears, Detroit locker, Eaton E-Locker, Traction Bars, AEM intake, Xcal 2
2010 VW Golf TDI 6MT