Personally, I define my trophy bucks more by a combination of age & uniqueness of antlers (rather than "score"). This one appears to have been a "trophy" buck to me. Never mind that I consider every deer I kill to be a "trophy" including more of them being does than bucks.
Not being able to see the teeth, and based more on the characteristics of the rack (rather than it's size), my best guess is this buck was 5 1/2 or older, easily could have been 6 1/2 (or older). And highly unlikely it was any younger than 4 1/2. That does not rule out the extremely unlikely possibility this buck "could" have as young as 2 1/2.