Here's one for sale that has the same p/n as yours. Whether its worth asking them for info/pics or even buying comes down to one of those time/money/risk decisions, everyone is different.
http://bluestarperformance.com/parts/ele...-1968-used.htmlThey claim the build date code is '67.
Some pictures of built up steel weights apparently from an earlier cast iron distributor for a /6. So I'm probably wrong about it being a special low production number part.
http://www.allpar.com/fix/electrical/distributors.html