I think MH people worry too much, look at all of the heavy equipment and farm equipment sitting out there with exposed hydraulic cylinders that are never treated with anything - and yours are under the MH not sitting out there in the elements.
Having said that, I spray mine with silicone spray every couple of weeks and usually when raising them if they've been down for a couple of weeks. Makes me feel good and doesn't harm the cylinders.
Bill
Nodwell RN110 out moose hunting. 4-53 Detroit, Clark 5 spd, 40" wide tracks, 10:00x20 tires, 16,000# capacity, 22,000# weight. You know the mud is getting deep when it's coming in the doors.