Thanks everyone. I spoke to Rudy at D & R yesterday to get the definitive answer from THE guy who built our boats. He said there are phillips head bolts through the exterior rails with nuts in the interior both covered with bungs. I really want to remove the rails to properly rebed them, I'm sure that has never been done on this boat. We have the gaskets under the standoffs and some of them have shifted and are exposed. The only way to fix that is to take everything off. At this point, I'm not planning to use the gasket material. I've been using butyl, so that's the plan unless I get into it and butyl seems inappropriate, then I'll go the gasket route. I'll take some photos and report back here once it's done or once I've made a huge mess of things and I need more support.