I have done many ARB's and even repaired quite a few from instal mistakes, i don't see why you would have to run out and drop the oil.
There is no need for friction modifiers, but it still should have a good hypoid type gear oil.
Unless something about the friction modifier make up attacks the seal or o-ring of the ARB i wouldn't worry about it
1995 Jeep gc ltd, 2005 Jeep gc ltd , 71 Dart, 73 RR 440-6pk, 78 Mag GT, 85 Power Ram W-350, 92 Daytona, 99 Dakota, 08 Ram 2500
Less than 8 is like playing with half a deck
Long Island Motorsports Association