These weights I believe came from Central Skin Divers in Jamaica New York.  Many dive shoppes back in the Vintage Scuba days made their own molds and sold them to their customers.  Unfortunately this practice has pretty much stopped and many of the examples are gone forever.  I find these weights very well designed as they are very flat and have dimples on the back side that keep them from slipping once on the weight belt.  It is my understanding that Central Skin Divers is still alive and well in Jamaica.