When I upgraded my transmission to one by DTT. He never said anything about replacing either of the coolers. Make sure the lines are in good shape or
better yet, if they haven't been replaced already, that would be a smart thing to do.
The original lines had the quick disconnect fittings with plastic keepers and have a tendency to fail.
Unless the original transmission failed and seriously contaminated the system, What would be likely to be wrong with the coolers?
DTT did replace the hose at the engine mounted heat exchanger with a braided line. Later I had to replace hose clamps on the rubber lines between the steel lines and the cooler at the radiator.
The dealer's mechanic did a sloppy job when they installed my new steel lines.