Utah and Colorado are a lot alike when it comes down to when big bucks are shot. The later in the year that you hunt the better chances you have of finding a huge one.
Most of the huge bucks that are hanging in stores, service stations, and tourists traps in Utah were shot in late November.
When I first started hunting you could hunt certain areas all the way into December when most of the big boys were hanging around haystacks or out in the open where they could be found.
If you look at the dates that a lot of the bigger bucks that were taken in Colorado back in the 70's and before you will find the same thing.
There are still great places to find these bucks but you are going to work for them. I have chanced upon a few great bucks but have never been able to get close enough for a shot. But I do have some that are better than average that were taken on public lands where it takes very few points to draw, but I got them back when it was a general hunt with no draws needed.