Depends on how far gone the finish is...
If the finish is so far gone that the wood has turned dark in places, then revarnishing will only hold the "dark" in forever. Some experts bleach the dark spots and then re-varnish. If it's just minor weathering, all you need to do is remove all the hardware, sand lightly and revarnish. A good spar varnish is all you need to use. It's a sweet cockpit arrangement for eating, isn't it. I love mine.
Best of luck,
Agaliha