So, this is really just a single sprite. The uploader appears to have just eliminated it pixel by pixel. So technically speaking it is highly likely this sprite doesnt exist in the game other than its full form. I could be wrong on this but... I believe these just slide.

In the GBA and other hardware/software comboes you simply slide the sprite under another sprite with a higher z-level. In the GBA this was accomplished with OAM attributes (0x07000000) for the sprite pictured here... ATTR1 for x position (to 511... ATTR0 for y coord. But on the plus side this a more versatile sprite sheet than a single door tile.