I assume he knows that because he has made other skins. However there is already atleast 1 d9 skin, I know I did it
. They still needs to be in the correct number sequence. D1 wont work.
So if there are 4 custom d9s in the game name if he names his D5 it will show up offline for him.
I have run into this same issue after a new skin is dl'd while in the main I go offline to check a custom skin I am working on I have to go back and rename my skin in the next sequential number.