A loose panel slides out at the back and can be turned around to show either "open" or "closed". That whole construction was made of leather and a hardboard panel was glued in between the two pieces of leather to keep things flat.
In the photo below take note of the thin black line, made with an extra thin sharpie, that gives a lot of definition to the carving that is being left uncolored (No antiques to go sit in the impressions and outline that carved figures.
The next one shows the back of the sign. You can see where the open/close panel sits in its pocket at the back - it is lifted out and flipped around at open and close time.
Some of the detail from the back shows an African Cape Buffalo, and not a waterbuffalo as most Americans think.
Here is some detail from the back - just having fun with gemetric background designs.
