But the buck's body is 6 1/2+.
For sure. He looks extremely healthy in that pic for it to be January and post-rut. I hope you can become more familiar with him over time. As mega mentioned, a fair amount of bucks range shift for a mayriad of reasons, and many times it is hunting presuure. I know all too well with some of the places I have hunted and the pressure we put on the deer herd. I'd have trail cam pics of bucks in spot A all October, then when the masses hit the woods mid November I would either lose them altogether, or pick them up on trail camera a mile away. Likely looking for a sanctuary.