Kenny,
I would have to guess that your Grizzly with the fat grip is a transition from 1959 to the 1960 model.
We need to remember that there are many of these transition bows from many years, where some features from both years are present. All features did not just change at the same day, hour, minute and second on the assembly line. Sometimes, it was an evolution over several days or more.
As I have said before, the criteria that I use to establish a year is first and foremost the riser shape, simply put the riser shape can not change, but everything else can be changed.
If we use Riser Shape as the #1 determining factor, your Grizzly would be a 1960.
If you use a different criteria as the #1 determining factor in this example, you will have to always use that same criteria in every other example for every other bow.
Laminations or wood type would not be an accurate #1 criteria to determine the year for many Bear bows.
Perhaps someone else has thought out this process in more detail and has a more accurate method of assigning a year to bows, and in particular those that transition from one year to the next...