I would replace older age class with 4 point or better deer. The reason is that bucks with good genetics will have 4 points at age 2.5, some will have four points at age 1.5. Three point restrictions will concentrate hunting pressure on the bucks that most likely have the potential to get big when they are young and eliminate hunting on bucks that have little chance of getting big.
I can certainly agree with that, as you are correct, many of the 4 points in eastern MT are 2.5 year old bucks.