Hi Nicklas,
Actually, there were two differences between the 70 (here we go again with the one year only routine) and the 71+ delay light harnesses.
Yes, you are correct that the 70 used a round barrel Molex male pin terminal for the the ignition key light that was changed to a Packard 56 male terminal.
The subtle second difference was inside the multi connection connector used and all of the harnesses. The 70 used a dual male and female terminal for two connections and the 71+ only used one male terminal with that same dual style connector.
There was only one light source for that special multi connector which was the switch panel title light, but provisions were made for an unknown additional light fixture that wasn't used. Since there wasn't need an addition terminal, in 71 they changed the terminal. I guess since the vendor had so many of those dual connectors available, the factory said ok to just use the stock connectors that was remaining.
Jim