Just as an aside here- is it even truly necessary to have a griffin of an obviously high level as an admin mount? You could just as easily gmbuff a lv 150, it wouldn't die and you wouldn't have to worry about appearances. My general rule with admin spawns is, if I wouldn't want a player to have one, I won't run around on one.
All that said, you rent the server, the sun rises and sets when you command it, so do what the hell you want, and let whiners whine.