Very few RV towables come from the factory with shocks. And most don't need them.
We tow ours (around 12k at the most when loaded) on dirt roads frequently and have no problems. Would shocks smooth the ride for the RV? I'm sure, but are they actually necessary? Nope.
But I know several folks that added them. They say they can't really tell the difference when actually towing, but stuff in the RV isn't jostled about as much. Your guess is as good as mine on how they actually know that
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Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD Duramax
Reese Fifth Airborne Sidewinder