At the moment I would not cover them up, as they are plastic and not metal, I cant see them causing any harm in the short term.
My corn used to rub against the glass and the the lip in-between the two doors for a bit, he soon stopped after he realised it was not getting him anywhere. He did no damage to himself.
just keep an eye on him for a bit, you could cover the vents with a sheet of cardboard with some small holes in it, stuck up with a small amount of blu-tac, making sure he cant get stuck behind it of course
He's curious as there are so many new smells and the vent is where the smells are strongest. If you cover the vent (and decrease the ventilation so not a good idea) he'll just rub somewhere else such as the gap between the glass doors.