A couple of things that will work against him....
- post 1965 J-45s have the smaller nut width (1 9/16, I think). Some folks looking for vintage J-45's consider that less desirable and prefer the wider nut (they got smaller in '64);
- adjustable bridge is another thing that was controversial and may detract from the value;
- is that a crack on the lower bout?
It should still go for a pretty penny tho' as they are highly collectable. You can read about them here....
http://www.provide.net/~cfh/gibson6.html