Alright, so yeah this DOES NOT work.
While it will show up in the character menu, it's impossible to actually mount the "super mounts".
I tried 2 variations.
First, Gave both normal and Super mount.
Login -> choose super mount, mount the mount, but it defaults to the First iteration of client id that it finds. Meaning, it chooses the normal mount.
Aka: 33 and 32 has same client id. Select 33, save, mount the mount, get id 32.
Tested with "speed" 100 and 1000, and when you re-open the outfit selection window, it shows that you are riding the normal mount.
Second, Gave only the Super mount. (thinking we could give/take mounts and kind of make an upgrade system or something)
When attempting to mount the mount, it acts like I have no mount, and just opens the outfit selection screen.
I'm assuming, because of the same issue as above, where it finds the first client id in the list, and the client/server assumes that is the one you want to use.
Thirdly, I attempted to create a script to Force my character to use a different mount.. but again I can only choose the ClientID.. aka looktype of the mount, not the Mount ID.
So upon logging in, while only having the super mount, I forced the character to have that looktype, and everything broke. xD
My character had no mounts, and until I restarted server (and remade like 4 characters) I couldn't even see that mount in my client anymore.
Conclusion,
I couldn't make this work outside of the character selection window.