I am not sure we are quite there yet

......
This buck scored 172 and change. PNW heckles in the trophy BT thread scored 14 points less after deductions. Gross scores very well may have been closer, start talking water displacement and things might get real interesting. In addition, it sounds like Heckles buck may not have been killed on his best year.
I agree there are distinct physical differences, but the same can be said for a mule deer from Sonora and one from Saskatchewan. A buck from eastern Montana can look significantly different than a buck from the Sawtooth range. But they are both mule deer.
I am not a scientist so can't tell you when genetic diversity and habitat adaptation start to blur into subspecies creation. But I am glad we have the diversity of habitat and genetic differences, it keeps it fun.