If an officer is using his revolver in combat, he is not doing his job.
No they did not and no they did not.
Arms where issued. And regulations clearly said what arms a soldier should have and if a unit for some reason had more than needed they had to hand them in to the ordonnance department for reissue to unit that needed it.
Both sides had a serious lack of revolvers. The CSA tried to help solve it by forcefully buying any revolvers in the hands of enlisted men in the infantry. Any weapons captured from the enemy or picked up after a battle also had to be handed in to the ordonnance department. (bring you own unit up to numbers Iam sure was done first)
So When we are talking regular cavalry the troopers did not have more than one revolver.
And it would be hard for a unit ordonnance sergeant to keep extra guns a secret, since if the weapons are not listed on paper you can't get cartridge for them. And if a unit managed to get extras, surely the word would spread and what ever unit that did not have sufficient numbers would make a issue out of it.
Officers who had to provide their own arms and uniforms might have purchased more than one.
And similar in irregular units men ight have more than one if they where able to capture them from the enemy.
Cylinders.
There is simply no evidence of this being done. The arms manufactures where not able to produce the needed number of revolvers... so they where not making extra cylinders during the war.
Prewar when you purchased a revolver is was not something that was part of the standard packages, unlike a case, bullet molds, tools and similar. There where no orders for extra cylinders. There is no evidence of extra cylinders being issued.
And imaging trying to replace on on a moving horse during combat...
Sure some random solder might have gotten access to one from a broken revolver or similar but again no evidence of this.
11th OVC publishe dthis video on the very topic a few days ago.