Oldwearer,
Yes, the gray percentage is evenly blended throughout the unit. The factory tries to keep the stock units as 'middle of the road' as possible so it appeals to the largest number of wearers. Some people may want more gray in the temple areas as this is very common--that would be a custom order and the the wearer can specify the exact percentage of gray in the temples and other areas of the unit. Note: with stock units the percentage of gray only comes in increments of 10%---so it's either 10% gray, 20% gray, 30% gray, etc.
Regards,
John