Hi I need some help with completing my bestiary in this game. I know you dont HAVE to but im a perfectionist when it comes to final fantasy games lol

and yes i have completed the game already, now im on second playthru for all the extras.

So far i am just before the entrance to eden hall, where the bloody great adamantortoise is stomping around, and i suddenly realised i dont have a bestiary entry for the targeting beacon, that the Bulwark enemy can drop during your fights with it. The bulwark appears on the skywalk near the begining of chapter 12, and i know you can backtrack and i did, but its not there, every other enemy is but that one.
Have i now completly lost my chance or is there a way to spawn it somehow??

I suppose this is mostly being asked to all the ff perfectionists, like myself who get crazed over these stupid little things lol any help would be appreciated!

thanks