Just browsing through the August issue of HPP and the lead letter is from Keith Seymour, who was a GM driveline development engineer for many years, and he states that the reason driveshafts are different sizes on the ends is very simple: so they could use an existing yoke. Driveshaft diameter is determined by "critical-speed requirements", and has to be strong enough in the middle so it won't jump and flex, but it doesn''t need to be that big at the ends. Therefore, if a larger yoke didn't already exist, there was no reason to tool one up. Much cheaper to swedge the shaft down.
So unless originality is a factor, maybe there's no real reason to keep track of it.
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