Here we go again...
The thumb safety was requested specifically to enable a mounted soldier to place the pistol in a safe condition with one hand so that he could regain control of a frightened, unruly horse. It was also noticed that...if the same trooper attempted to reholster the piece during such an episode, that...under the circumstances...he might not remember to take his finger out of the trigger guard, or the pistol could be pushed out of battery if the slide was free to move. If the gun was also dirty at the time...it might not return to battery without the trooper using both hands.
The thumb safety was not...as many believe...adopted so that the pistol could be carried in Condition One. Neither did JMB or anyone else intend for the gun to be carried in C-1. The user was instead given a choice as to the modes of carry...1-2-3 or4...depending on how critical the situation was/ is.
Oh I wouldn't doubt it but... I have never heard of or seen a model out there that was sold to the commercial or military populous that's was labeled and or name the 1910.
And you never will. There were only 8 of them produced, and numbers 6, 7, and 8 were retrofitted with the prototype thumb safety for testing and evaluation. Of the original number....there may be only 2 or 3 that still exist without the safety...and they're socked away in a museum somewhere.
The grip safety is redundant, but it's not unnecessary...or it wasn't in 1912. Remember that this gun was designed primarily for the US Cavalry.
In the event of a dropped pistol...if dropped from shoulder height while the shooter is on horseback...the pistol will likely flip and land with the muzzle pointed up...possibly at the horse or its rider. Without a positive means to block the trigger, the trigger will move backward on impact and cause the sear to move. If the impact is sufficient to move the sear far enough to miss the half-cock notch...bang. Remember that the old guns had long, heavy steel triggers.
Pictured below is a photograph of a 1910 prototype, sans thumb safety. Courtesy of Charles W. Clawson.