10+ years and counting, wooden stands, a block from the beach.
Not only for the stability when parked in the driveway, climbing in and out but not seeing 'er weave in the wind just a plus for me.
Not working the jack mounts day in and day out, especially on the OPs 29 year old wood framed camper, hanging by its corners I would think a proactive thing.
Yes most campers are designed to be supported by the jacks, but they are also, primarily IMO, designed to be supported by the floor, albeit by a uniform flat surface (truck bed). As long as your not point loading the bottom or unevenly stressing the bottom & structure and most of the weight still on jacks it should not CAUSE a problem. (though I'll admit ours has spent quite a bit of time setting on the stands alone).
Personally I do not interpret any mention in owners manual precluding adding a means of stability when out of truck. Whether you need or want to a matter of choice. Though half a thought on how thats done should be given-IMO.
