those textures are on audience.pac inside bord.pac
if you use the psp version the textures are simple gims in the ps2 version the textures are in txc format
in my opinion dont try it that take a lot of time and work because its like pacs inceptions, pacs inside pacs and pacs inside those pacs but if you still want to mod them usually all the wrestlers have 4 boards and the ids are like this:
id of the wrestler + the number of board, so lets say you want to mod edge's first board, the id will be:
"1101" in decimal but then you need to convert it to hex so the id for edge's first board is "044D"