I would even be leery with using a dealer unless you watch them and have a good idea of what is right too. First RV, Dealer setup WD hitch. They did not do it right, They used a battery operated impact wrench. I drove 5 miles and nearly lost the trailer with the ball loose on the last threads before coming apart.
Bought a new RV this spring. They moved the WD hitch from the old to the new and said they were done. I took one look and saw the trailer was nose really high and the WD bars did not even engage, Had them lower the ball to level and then adjust the L-brackets for the bars and they "eye balled" the level and said everything was good. But in reality, the WD setup is still not setup properly. I temporarily raised the L-brackets to engage the WD-bars and that helped but I will still need to have the hitch readjusted to be properly loaded.