While the 23D were made of cast iron. The transmitter mount is a butterfly mount. 

 The Gray 23D was featured in the Gray Telephone Pay Station catalogue.  

 The vault door has a lock and Key. Japan black paint that is original has been cleaned up nicely. Coins chime when hitting the gongs Each coin sounds differently This one sat in a collection for a very long time.

Has sign on the front which is covered with glass.

The top closes perfectly with a screw . That is so nicely done it almost looks like it was factory done.