That's a good looking 3 yr old. I live and hunt in north central IL, and it's been my experience if a deer has the genetics to hit 150 at 3 he will usually make 170 at 4. You got a keeper there.
It would be tough to pass on that guy! With my bow I probably would have shot him at 2 thinking he was 3... Good luck hopefully he will make an appearance on the show it would be sweet to see a live update even if you don't shoot him.