I removed the headboard in my Adventurer Class A a number of years ago. It too was attached to the wall with short screws hidden in folds of material.
There were 5 or 6 such screws - 3 on each side and at least one at the bottom, if not two.
You said "
penetrating the outside wall of the slide by about 1/2 inch." Did you mean "inside of the wall" rather than outside? The screws were not sticking out the slide wall of the RV were they?
I don't know first hand about any wall studs in the slide wall. I doubt there are, but that's purely my opinion not any kind of knowledge speaking.
I put the headboard in my Attic and bought some wood like vinyl wall planking to put on that wall in my bedroom. It looks good but I bought a weathered gray "wood" planking and it looks just like the gray wall paper it's covering. You'd not realize it's there. I should have chosen something a different color. Here's a link:
https://www.stikwood.com/collections...om-wall-planks