Sorry for the slow response. The DiMarzio I got about 5 years ago NOS from a dealer. It was from 1982, and still in original plastic! According to the seller, this was not a retail released series, and they were used mostly in the Kramer and Dan Armstrong Modified aluminum neck basses at the time. The only reason anyone plays one of those back breakers is the tone out of those pups! Crushingly punchy and full of life, they even killed a lot of active versions for output.
Not really any info, but you can see them in the pics here starting with the 4001 series, look for the p=style cream white covers:
http://www.vintagekramer.com/alum.htm