i definitely would NOT say he is 4.5. He does look older from the side but seems like he just has a lot of muscle. Head on you can tell he is not an old buck. I would guess 3.5
A buck is considered to hit maximum maturity (antler size) at 5.5-6.5 years old. He definitely looks older than his antlers would suggest, but I would guess him to be 3.5, maybe 4.5.
Interesting... I think the issue is that the muscle tone tells one story and the rack and neck girth tell another. Hard to say... almost certainly 3.5 years or older though.