I’ve just bought a Yeti SB-66 which I believe to have a 2012 RP23 however, the shock’s pro-pedal knob says 0-1-2 rather and 1-2-3 and won’t move, only the pro-pedal lever moves. Can anyone tell me if the RP23 is a 2012 and whether this is correct? Should I be able to turn the pro-pedal knob?

Yes, it is the 2012 version. Looking down on on the shock, with the lever pointing out left you have propedal setting 3 on. When facing right you have the option of 0,1 or 2 (0 being no propedal at all,1 being a little bit of propedal, and 2 being a bit more propedal) To change this option pull up on the dial with the numbers and turn it to the desired setting. It pulls up about 1 or 2 mm and then you position the number you want in line with the blue lever.
Generally speaking you set this to whatever you want and leave it, rather than adjusting on the fly. I would set it on 0. That would give you 2 real options when riding, that of no propedal for descending, and propedal 3 for climbing.
Make sense?! Didn’t the shop take you through stuff like that?

Thank you.

No, bought frame only and come from a Float R so not used to all the adjustments.

Colin has it right. Basically fox want people to use the settings more so give you 1 pro pedal setting for climbing (lever to the left when looking straight at it) and the 0-2 settings are your compression adjustments for different types of terrain for general riding and descending. The gumf is that with lots of berms you may wish for slightly more compression (setting 1) to aid speed out of the corners helping the rear be more taught and say setting 0 when its rocky, but as colin has said you will just leave it on 1 setting all the time.