The hatches are fiberglass so refinishing is relatively straightforward. Remove the hatch, disassemble, sand down to solid material whether paint or fiberglass depending on sun damage, coat them with a linear urethane (catalyzed urethane system), reassemble. If Sam's doesnt have the gaskets, Chesapeake rubber certainly will. Im not a big fan of silicone sealants but sealing the plexiglass in a compressed gasket situation is one application it excels in.