I am sure Rival's design saved a lot of deck leaks from chainplate working (moving under stress) but to get that kind of part machined will not be cheap. To do it right is a lot of labor or an NC programming job.
It appears that Rustler Yachts bought Rival-Bowman.
Maybe they can source those eyes for you.
http://www.yachtingmonthly.com/news/406568/rustler-yachts-buys-rival-bowman
Good luck.