I have several of those prints in my stash, and they are not all as old as the 1960's. (I started quilting with the Bicentennial era.) You won't be remiss in using a bonded polyester batting, which is what we used in the 1970's, but W/N would be even nicer. Any 100% cotton in a compatible solid color could be used to bind it; I'd try to match the green.