[Black Beauty]

Originally Posted by cotten

Martin has made an HD-28P, though I don't know if they still do. Here's one. http://www.elderly.com/items/10U-3392.htm

Martin used the P designation for low-profile necks when they were introduced before standardising it - so that HD-28P listed is in fact the same as the current HD-28... But an 1989 version. I wonder if the one the OP saw was also an HD-28P from around those years.