You can go back to Chocobo Forest, and if there are no Chocographs to find there, the Moogle there will tell you before you play. Otherwise assume you can dig more up. Also, I think once you have the boat and a light blue chocobo you can get to Chocobo Lagoon as well (though it's a bit of a zig-zag route on the chocobo as I recall) and find more Chocographs there.