I had the same stuff in mine. I already had a replacement radiator so I swapped it out. No need to change it out unless it's leaking.
The rusty stuff is what came in the Jeep from the factory. I just replaced it with the green stuff that says " suitable for all vehicles regardless of color of antifreeze" I used Peak i think.
1998 4.0 5 speed, Superior super 35 rear, Superior super 30 front, Yukon air lockers x2. 3" Terra Flex suspension lift, 1.25" BL, 1" MML War 8K winch, Dick Cepeck Radial F-C 33/12.5/15.