I was able to find Mark Plastics in Corona CA. The number is 951-735-7705. They have the original molds and were able to remanufacture a new set of windows in about 2 days. The cost was 1100.00. They use a polycarbonate acrylic now which is much stronger and scratch resistant than the old plexiglass. The improvement to the appearance of the boat and ability to see out with crystal clarity is amazing. Certainly worth the $$.
PS. Mark works with you in person and is a great help.