any good waterproof materials?

Originally Posted by SouthArk370Z

I'd try gobbing some RTV on the bolts that pass through the body panel as a temporary measure to keep water out and then obtain the proper materials for installing the wing. Elastomer washers and a small bit of RTV on the washers/bolts/nuts should be all that is needed if the installation is done correctly.

RTV/silicone would not be my first choice for mounting the wing unless I were sure it would never have to come off again. It does need to cure at room temperature, if you can't find a warm place, wait until Spring.