Towing w/out weight dist -- am I being too conservative?

My SIL towed his comparable weight toy hauler no WDH for a few years on two different Ram 2500s, one diesel, now gasser, before just getting a used fifth wheel.

I’d contact the WDH maker and give them a what’s up with this message. 4 years on a WDH should have ZERO probs on the WDH unless you left it in the weather.