That spot usually had a foam/rubber pad where the adhesive residue is that would keep the coin box secure inside the door. Not sure why there's a rectangle around it, but I'll take a look at some of my older photos and see if there's anything there.
I thought it had something to do with the coin box, but I wasn't sure what. I've never actually seen one of those pads, so they must not hold up very well over time. Can you get the same material to make a replacement?
