Edit - There are sources supporting both Lemat revolver and Lefauchaux revolver as correct answers to this question, so credit will be given for either answer.
Wow! Francis Barnum, the sculptor of the over 150 pieces I have now, really did his homework. I just looked at the Chilmark he sculpted of JEB getting shot on his horse---in his hand is a LeMat! I never noticed that before-thanks for the trivia!