The RPG schema is part of the v1.1.4 release.
All schemas will have the same functionality, they are just visually different. The main difference is the default layout.
For the Classic schema the default layout creates a main menu with the inventory inside.
The RPG schema create multiple floating panels.
Since all schemas have the same functionality you can do the same layout for RPG and Classic, you will just need to use the UI Designer tabs to create the UI and maybe fiddle around to place the panels in the place you want.
Just a reminder that Schemas are just a collection of prefabs and scriptable objects. The UI Designer is just an Editor that spawns those prefabs in the scene at Edit time (and hooks up references for you to speed up your UI editing workflow).