If the cracks aren't to long you could put the risers on which have a larger base to cover them. Or you could get a stainless acorn nut , take the rack off and use the nut on top and a bolt through the bottom to close the holes. I seem to remember a post a while back about a bolt kit made by someone similar to what I am referring to but I can't find it now. The paint and labor will probably cost you more than a new lid. There are 3 or 4 Salvage yards in Tennessee if you want to find a used one.