You have nothing to loose by trying to repair it. I wouldn't use JB weld even though it is strong. It doesn't have the fibers that will be crossing over the rails to give it enough strength. If you do go with JB Weld or Marine-tex (both are similar), and it fails or cracks, you could grind away the repair epoxy and try again with carbon fiber and epoxy.
To do the repair I would grind/file down the bumps where the rails go in and apply layers of carbon fiber with epoxy over the rails.
The carbon fiber I use looks like straight human hair in jet black. There is something sold by Wick's Supply that is West System unidirectional carbon fiber with a part number of 702. West may have put some fibers that run across the straight fiber to keep it neater. Keeping these fibers in place was a problem on version of the carbon fiber that I have.
Wick's Aircraft Supply
This look more like the stuff that I use:
JL Smith
By the way, I think that even though this a carbon fiber component and some C & V'ers have an aversion to carbon fiber, many C & V'ers may have the knowledge and motivation to repair a components rather than buy another one. I originally bought this carbon fiber to strengthen a wooden sailboat.