Not really a true indication, but just an observation: around 1992 or so I wanted to get two more 511B borns. I have two 802D drivers tucked away that I bought new in 1968, and replaced with 808-8a in 1971 I think, when they first came out, Well, the new ones are black, and to me the quality of the welds is not as good. They are still in the cartons, although the cartons have suffered from a roof leak (humdity) in my garage. Turns out, now I have 8 511Bs. Also 4 dead 416 small and large frame. and some other stuff.