colt official police. circa 1940

You need a better picture showing the entire grip, but they appear to be a now-valuable set of Colt First Type Target grips.
These were Target type grips used on the Colt Officer's Model Match, original Trooper, the Colt 3-5-7, and on the Colt Python.
Only the Python had Gold medallions, all the others had Silver.
These Target grips were used by Colt from about 1953 to the late 1950's.

These would not have been the original grips for your gun, but people installed them as an after market alteration.
These days, the First Type Target grip often sell on auction sites for in excess of $250.

Here's a picture of a set with Gold medallions made for the Python:

Originally, your Official Police would have been fitted with the narrow Service type grips made of checkered walnut with Silver Colt medallions:
Here's a pair of Service grips, only with Gold medallions as used on the Python. The same type of grip was used on most Colt revolvers from the mid-1920's to early WWII, then again from the mid-1950's to 1969.

a better pic.

what is this gun worth?