The polyurethane mod should work no matter where either the poly-bushed arm or the bracket was sourced from. Meaning that you could do the same thing to the LCA bushings.
While you're at it, you might shape the flat ends of the poly into flat cones like this . . .
View attachment 72280
If you're really serious about minimizing 'bind' (such as for road course driving) there's another trick you can try (not sure I've drawn a sketch of that one yet). This additional mod would be more applicable to the UCA, not so much to the LCAs. It involves a little drilling in certain places, and some care to avoid drilling too deep.
There is an advantage to swapping the both the arm and the bracket up to the later arm & bracket. The arm is about an inch longer, and the rear suspension's side view geometry remains a bit more consistent throughout its travel as a result. Something else you probably need to be more serious about than most folks.
Norm