Documentation for Collectibility

Hello! I am new to OMHPS and have only done a few photo shows before. I am working on uploading horses, and was wondering what type of documentation should be uploaded for collectibility of models? I would like to enter Feis, my diorama prize model from 2020, and wasn’t quite sure what to provide. In his description I have listed that he was the BreyerFest diorama prize model from 2020, a run of 28. For documentation, do I need to do more than this? Should I upload a photo of his COA, or will a link to IDYB or the BreyerFest Blog be enough?

Either of those work! COA is always a good idea in collectability if the model came with one, otherwise a link to/screenshot of IDYB or the BreyerFest blog is perfect, too :)