The original Lego Keychain wallmount was made of cardboard with a lego a lego 6 x 16 baseplate glued in. This is a replacement part for that cardboard only, with the same (hidden) screw distance.
You can of course use it to make an extra or new one, if you got a 6x16 baseplate laying around somewhere.
Just glue into the rectangular space
The author marked this model as their own original creation.