Don't worry too much about losing the jaw bones and not being able to age it. Aging jaw bones is really inaccurate after the deer is about 3.5 years old. Even then, studies have shown decent variation in tooth wear with deer younger than 3.5 years (especially between geographic areas and diets), as well as the ability of trained tooth-agers to identify deer age from jaw bones of known-aged deer. Old is old, and yours looks to be a really old boy! Awesome buck!