http://www.ebay.com/itm/SMC-Pentax-A-50mm-f-1-2-MF-Lens-Serial-1414748-New-in-Box-/261370308717?pt=Camera_Lenses&hash=item3cdae2686d
It is claimed that it is a brand new item produced by Asahi Optical Company long time ago. Since I have also many of those excellent Asahi glasses, which are all in very good condition, I must be rich if I sell them! ;-p