I do not see anything in these rules specifically probiting a revolver, but Rule 4.2.7 is named Production Optical Pistol. In my world, pistol refers to a semi-auto and a revolver is a different type of handgun HOWEVER the entire 4.2.5 rule is titled Production Pistol and refers to revolvers in a few of the subsections, so I don't know. It does say in rule 4.2.5c that revolvers are exempt from having to fit in the 'box' and 4.2.5f states that a revolver can have a 6" barrel. I would make damn sure of this before showing up with it though. I am not anywhere close to being the authority on this. These are just my interpretations. In other words, don't expect "But Joey said" to have any standing with the CMP!
As far as shooting the Plate match standing, it does state on Table 4 that the Position will be "Standing". In Table 2 (Practical) it states the position from 15, 25, and 50 yards to be "Standing or Prone", while in Table 5 (Moving Target) it shows the Position to be "Standing Only". These terms may need to be standardized and clarifications made. Having to shoot the plates standing the entire event would definately lower a lot of scores. Mine included!