RE: Big Buck Barometer
I have seen first hand in my part of the state bucks that are 3.5 years old and 135"+, but as Rybo said many of these are on locked up land that is unavailable to anyone and most turn into ghosts once they are hard horned. I do not see many deer that I would estimate as older than 3.5. If you see one it's like seeing a shooting star. You pay attention and make a mental note of it.
So, while those deer are present hunting them is another story. Not to mention that the ones that aren't poached upon reaching 3.5 become nearly strictly nocturnal so the only realistic chance is to set up on a funnel and hope a hot doe will bring one out of hiding in a love crazed frenzy. It happens, but it's like winning the lottery, right place, right time, and a lot of luck even if you have stacked the odds in your favor.