Both standing and wall sign GUI backgrounds cannot be retextured independantly from the block

What is the bug:
In the edit screen of the sign block (for both hanging and wall variants) the sign shown in the background renders based off of the sign's model rather than off of a texture, where as in the hanging sign edit screne a texture is used for each wood type variant.

Screenshots/Videos:
Hanging sign textures

Possible fix:
Attatched is a zip file containing textures that could be used for the edit screens.

Notes:
It is expected that just like with the hanging sign, both standing and wall sign variants would have a unique texture used inside the edit screen. Without it, resource packs are disallowed the ability to change the texture shown in the edit screen seperately from the respective block texture/model.