replacing window seals 84 381

Hello , anyone know s what gasket material will replace the ports window seal on my 1984 381, and who was the original manufacture? are they still in business? what was the outside ring constructed of? what was the coating system used? where to get the materials top rebuild them?
Thanks for any help. jon newman
Update on the Kenyon spar, we will step the mast latter this week, its been a real expierence both in time and costs but I think it was worth it its a great ride.