The chin does not bother me. It actually gives the watch a unique character. As for the price, I see it differently. If the AD is giving you a very good price this gives you a margin of safety when you go to resale. However if I acquired this piece it would be a keeper so resale value would not figure into the equation. Either way if this piece sings to you I would get it. New old stock is a great thing especially at good prices. I would jump on it.
Please let us know what you decide.
Best
CB