I took the rudder apart this winter. Removed the blade from the plates that secure it. When I looked at the hole that the bolt goes through that the rudder swivels on, I noted a plastic insert that that was held in place by white caulk. The insert was much smaller than the hole in the rudder. Does that sound like a factory part or is that something a previous owner came up with? Could I have a stainless piece made with a better fit?