Notables such as John Taffin are convinced that Colt was a southpaw, and says so in different places in several books. For example, in Single Action Sixguns, Chapter 10, he says:
"Sam Colt was left-handed, that's why the Colt Single Action has the loading gate on the right side!" This is one of the first things I heard from Bill Grover as I met him for the first time at The 1987 Shootists Holiday. I didn't have the heart to tell him that Sam Colt died in 1862 and probably had nothing to do with the design of the 1873 Colt Single Action, the famed .45 Peacemaker.
Even if Sam didn't design the Colt, Grover's point is well taken. The Colt Single Action is definitely made for a left-hander. I know that I personally always load and unload my Single Action Colts, Rugers, etc., by switching them to my left hand.While discussing this with my boys recently, one of them pointed out that the trigger on my Uberti Hombre is off-set in the trigger guard, to the left side of the frame. Sure enough.
The trigger is off-set to the left and the loading gate falls naturally under the left thumb. There may be something to this "Sam Colt was left-handed" theory after all.