Keith,
You will have to get the dimensions and size from another 65
Caravel owner, the chances of you finding an original curtain is slim & none, I think you could stand in the shower with a new curtain and see from the inside what coverage your going to need, and for the sides I sew'd in a few velcro strips so it would stick to the wall & keep water in as much as possible, you can sew in the top tabs for the rail as well. I had the old one to copy from when I did mine so it was easier but I think you can do the same without it. Hope this helps.
John