When used in a game, they will look almost the same (see the comparisons below). However, RMVXA has additional colour settings that override the background graphic normally displayed in RMVX, resulting in only the border and cursor from the windowskin showing and the background becomes the default window colors.
As you can see, the windowskins are the same, but with the background overridden by the default colors in RMVXA.
There is a script "cheat" to overcome this problem. Insert this snippet between Material and Main:
class Window_Base < Window # "true" to enable override, "false" to use default USE_WINDOWSKIN = true # Update Tone def update_tone self.tone.set($game_system.window_tone) unless USE_WINDOWSKIN end end
The end result is this:
This is the Status Screen using the RMVXA windowskin, which is the same as the original RMVX one, without needing any conversion.