You have two Choices
You can either make a mounting plate out of a piece of stainless. Drill the holes to fit the the V-cleat mount and then drill holes for the cam cleat. Not real hard to do. You could also fill the old holes with Marine Tex and drill new ones. The Marine Tex will not be quite the same color but probably close enough. It is quick and easy to do and after a little sanding you will probably be the only one that notices them.