I'm with Northshore. My experience is nothing will stick to it, after the fact. The very fact that adhesion will deteriorate over time is the death nell for a wood frame camper, over time. Why? Weather. Sun. Freeze/thaw. Leaks. Seep. Delam. Mildew. Rot. Structural collapse. Death. Unload it for the last time at the dump.
If you only plan to have somebody's old recently siliione laced camper for a short time, silicone caulk will work for you.
There have been exhaustive reports on this TC forum some years back on the use of different caulks for sealing TC's including what products work best in this situation. One guy had a wide ranging photo essay with text of his complete re-caulking process. It was a marvel to behold. Since we have quite a turnover on here with folks coming in a fading out, I would take advantage of the corporate memory of others' experience. I did. Still no leaks.
I put together a saying in college when I still had a fresh mind:
We know what we know. We don't know what we don't know. But, we don't know that we don't know what we don't know.
jefe