It's one of 381 Grand Coupe convertibles with a 318 auto. Nobody can tell you how many were painted FJ5 because Chrysler never kept records like that.
Some people quote registries like Galen Govier's saying, "it's one of three painted red, etc..." but that means that Galen only has three red ones in his registry.
Chrysler did keep track of percentages of options but even those numbers are across the entire model line-up....so you can't get a accurate number...no way...no how...