I noticed the same thing on the black synthetic (smaller grip) vs. wood (larger grip) stocks. I also recently looked at an Encore with a laminate stock at a local gun shop, and the grip seemed just like the wood stock (larger than the black synthetic). I've never picked up an Encore with the Realtree stocks, but I was told that they are exactly the same as the black synthetic stocks...just in camo.
Also, you could probably email TC Arms and get more definite answers to this question.