It’s a pretty unusual design for its day. Are those the sliders that fit into the mast track? You should use the search function to look for other Flyingfish posts and see if there are any ideas there on sails. Otherwise you may have to get a sailmaker to make one - probably not a copy cause it’ll be expensive, but at least something serviceable.
my above post was poorly worded and meant as a suggestion.....to measure your sail and find a currently available sail with close or similar dimensions....the Hobies being a potential replacement. Don't let the bolt rope be a deal breaker as correct sized slugs will fit just fine in a mast track previously used on bolt ropes. Sailrite has a decent selection of slugs too...or bolt rope for tbat matter too! Same with the full battens....either/or etc, etc,
Lastly, Sailrite has sail kits if you're so inclined....with most home machines being able to sew thru the thinner layers of sailcloth But EBay and numerous business in Florida are flooded with used sails...all shipable.