I recently found this auction:
Colt Police positive : Revolvers at GunBroker.com
The letter was in the original envelope attached to the back of the case w/ freezer tape. The shipping info is nothing spectacular. But, it is neat anyway! The letter dates to 1961. The gun is rough but functional with the grip frame "converted" to round butt and a broken hammer spur. The round butt stocks are in very nice condition though!
It turned out the typed card w/ the gun info on it was actually the business card of the man who's ordered the history letter. He built frames for grandfather clocks & did other custom woodworking. He must have built the shadow box.
This had hung on someone's wall for a long time!!
Best,
Charles