What would you expect them to look like if they were not manufacturer installed?
My point being that a clean hole does not make something manufacturer installed. There are a lot of meticulous people out there that are capable of installing a couple of screw eyes without drilling a hole with an axe, and pounding them in with a BFH.
That said, my guess is the previous owner of the camper put those eyes there for tiedown points for the same reason you want to use them. I'd still want to know what they're attached to before I used them though.