The Fitz trigger guard conversion wasn't as popular on Smith & Wesson's because a screw, spring and plunger that tensioned the cylinder stop was nested in the front/top web of the guard, which prevented the guard from being cut fully away. This wasn't the case with similar Colts.
The original concept was a revolver to be carried in the side pocket of one's pants. Rather then use a holster Fitzgerald had his pants fitted with special leather pockets, and sometimes he carried not one, but two guns.
Other features included cutting off the hammer spur and checkering the top, rounding the bottom of the butt, and sometimes making it shorter, installing a (give or take) 2 inch barrel and cutting the ejector rod to match, and carefully hand tuning the action.
The trigger guard was cut away so that a user could get their finger on the trigger, even in the tight confines of a pocket - and if necessary fire while the revolver was still in the pocket. This of course would only be done in an extreme emergency. Removing the front of the guard also reduced some of the revolver overall bulk. Considering the weight of the double-action trigger pull, safety was not an issue.
While Colt made the guns they did not catalog them. They were a special order item for certain special people, who for the most part were law enforcement officers of one kind or another, or members of one of the military services.
Not all Fitz Specials were pocket sized however. A few were ordered with full length barrels, and with or without hammer spurs.
Fitzgerald, as well has his usually hand picked customers, knew that a gunfight could be close and quick. One could stand with his hand in a pocket with it holding the gun and ready to draw - while not appearing to be threatening or even armed. No other way was as fast. His modifications were intended to make things slightly more sure (nothing to snag during a draw) and a bit faster (finger on the trigger and ready to go).
The professional gunfighters of the Fitz era that used his "Special's" would I think, look at today's Internet critics and just grin.
In a conversation, Jeff Cooper once said that one's opinion on anything was as valuable as their experience and knowledge of the subject. Does anyone here claim to know more about gunfighting and gunfights from actual experience then the individuals I mentioned in my earlier post?
Thought not...