Colt and/or Fitz made several models of pistols with cut away trigger guards and, on revolvers, cut off hammer spurs.
These genuine factory models are very rare, and the vast majority of them floating around are home-made copies.
Among famous Fitz owners was Charles Lindberg who was carrying his Fitz on the day he gave testimony against his son's kidnapper and murderer.
Another Fitz owner was famed Texas Ranger "Lone Wolf" Gonzalez who's two Colt 1911 .45 autos are in the Ranger museum in Waco.
These two 1911's have cut away trigger guards and are profusely engraved and inlaid.
Fitz himself was a HUGE man and HIS Fitz Specials were a pair of Colt New Service .45 revolvers, which he carried in special lined front pants pockets.
(In those days, mens pants pockets were larger then today).
Fitzgerald was said to be blindingly fast with them.
Pictures of Fitz guns showed up in gun magazines from time to time, and within 30 days, otherwise good revolvers showed up in the stores as trade-in's.
The "do-ers" thought they looked racy as Hell, but soon discovered just how unsafe a revolver was with a cut away trigger guard.
In addition, if given a good bump, the guard could easily bend, blocking the trigger.
The Fitz was very much a specialty gun intended for people who knew exactly what they were about.
Others found out that there really isn't any safe method of carrying such a gun, and even holstering it in a proper holster was dangerous.
Here's the identifying characteristics of a genuine factory Fitzgerald Colt Detective Special.