A little bit of info..
If you own a 1985 C-30 the biggest issue is that, to save money, Catalina, until 1988, laminated plywood into the keel stub. When this plywood gets wet, which it eventually will, it can begin to delaminate from the top and bottom fiberglass skins. I actually had to do this repair on my C-30 and it was NOT a fun or cheap project. On the C-30 you have an external lead keel, as most fin keels are. If your keel was covered in layers of fiberglass and gel coat you would not need keel bots because you'd have whats referred to as an encapsulated keel.To tell if your keel stub is perhaps wet first dry the bilge completely and then use a moisture meter on the inside of the boat paying close attention to the areas closest to the keel bolts.It is my opinion that the plywood keel stub is the major cause of the Catalina smile. While it does happen, on occasion, to post 1988 boats (post 1988 boats have solid fiberglass keel stubs with NO wood) it certainly happens with far less regularity than on pre 1988 boats. If your keel stub has moisture in it then it should be addressed SOON as crevice corrosion of the keel bolts is what happens next...The boats did not leave the factory as you describe, glass and front and at the trailing edge of the keel only, and this is a sure sign a PO was trying to either hide or repair the Catalina smile..