That is indeed a VERY rare 3" fixed sight model 19-3. To my knowledge it is uncataloged, and not listed in the SCSW.
That 19-3 was part of a special order for the French Secret Service. I don't remember the official title of that agency. IIRC they are referred to as the "Presidential Hunting Party".
The overuns were sold to the FBI, with the remainder, 75 IIRC, sold on the retail market. A few years later there was another small run done for the Royal Canadian Mounted Police.
That 3" fixed sight 19-3 may just be the ultimate concealed carry revolver.
Were I you, I would spring for the $50 letter from Roy Jinks to document its pedigree.
Very nice 19, congrats! If you ever wish to sell it, please PM me. Regards 18DAI.
I checked my notes. The 3" 19-3's with fixed sights were made in 1973. The serial numbers should be in the D63900 range. 200 units went to the French Government agency. Hope this helps!