Before jumping to worn out front end, OP never even mentioned how many miles or how it drives.
It would have to be high miles, defective or beat on for a relatively new solid axle truck to have worn ball joints.
Since OP didn’t provide a lot of clues, most common would be excessive toe in, or under inflation.
It’s not common and really strange that 1 front is overall worn more than the other apples to apples.
Again, no clues here. Was it on the RR before and got more worn?
Is it smooth or chopped wear? (IE bad shocks or balance or ….)