I looked at the '12's and yes the HCR has Evol R's atleast the 4 stroke HCR I'd assume the 800 would be the same way.
I don't think any of the production HCRs will come with R Evol shocks. If you check the 2012 Cat accessories catalog on pg. 101 you'll see 4 different models of fox floats: 'Fox Float 2', 'Fox Float Evol', 'Fox Float R Evol', and 'Fox Float RC2 Evol' (X model). Only difference I can see between the Fox Float Evol and Fox Float R Evol is rebound adjustment.
As sierraclimber noted Fox only offers the R Evol with rebound adjustment. Also note that the Fox Float Evol in the Cat catalog is $150 cheaper than the R Evol. I figure the Fox Float Evol is a model Fox made exclusively for Cat since it's available as a Cat accessory, but not through fox directly (at this time at least).
The Cat HCR specs for the 800 and the 1100T specifically use the term 'Fox Float Evol', not 'Fox Float R Evol'. I'm speculating here and have not confirmed this with a dealer or rep, but what makes more sense? Cat putting a cheaper and exclusive shock on their production models that still uses the Evol brand but without rebound adjustment, or a more expensive shock with adjustable rebound that might not be utilized by "Joe" rider?
I don't think the lack of rebound adjustment is too big of a deal for most riders either. Although I like having the ability to adjust rebound with the R Evols on one of my sleds, it's kind of a set it and forget it option that most people never play around with much (now Hi/Lo compression on the other hand....) You should also have a pretty good knowledge of the effects adjusting the shaft rebound of your shocks has on handling and control. Let's face it, most folks don't want to be bothered with this level of adjustment and perhaps it's a performance and liability concern for Cat. Mess around with rebound adjustment without a good understanding of its effects and you could turn your sled into a crappy handling and potentially dangerous machine.
Just putting 2 and 2 together here. If anyone has more specific info from a dealer or rep, I'd love to be proven wrong.