Vintage Post Office Door Mail Box Bank Flying Eagle Circa 1920+

Vintage post office door bank (single-dial combination).  This is an interesting piece.  Door has a single eagle and is numbered 1178.    It is a combination of an old post office door and a wooden box that can function as a bank.  Box is made of Oak.  Box sits on gold balls attached to bottom on the bank. 

On the bottom on the box is a label:
Stockmans Supply
Conway Kuykendall, Owner
401 Thompson Lane
Canyon, Texas 79015

Box is stamped on the bottom with number 689.  The combination to the lock is unknown.

Approximate box height is 8", width is 6.75", depth is 5". 

Nice conversation piece.