Wooly White Rhino

Wooly White Rhino Mount.
When it will be released on Icecrown Realm Store?
Frostmourne Realm has it already, it costs 49 Coins.
Is it Boe item as Magic Rooster Egg? Can players buy it on Frostmourne realm, leave it in inventory unused, transfer their Toon to Icecrown Realm after 2021 April 15? And then Put it on Store or trade to alts? This is really cool mount, want to purchase it. ( also if players will transfer their Toons from FM to ICC realms with they keep all items, inventory, achievements? )