There was a thread around here a while back that had a link to a company that sold all kinds of rubber plugs. I just use duct tape. Just cut it clean. U don't see it when the hood is on anyways.
Pics?
My local hardware store sells round plastic plugs in the Hillman section that could be glued on or whatever.
Something like these: http://www.lowes.com/pd_139442-37672-881278_?PL=1&productId=3013226