Looks a bit weird - wonder if she's had a tail strike at some point? Doesn't look unairworthy to me, just a little strange. But I would go over that tail area with a fine tooth comb, just to be safe. You don't want weak tails on Commanders.
On my 520, they found many of the stringers to be completely off or sawn through! Very scary, but I fixed it. I also had some dents and mis-formed bulkheads, but we corrected it with some doublers.