Dual point distributor ID question

To me it seems totally weird that they would put a different part number tag SCREWED to the BODY of the distributor just because they wanted to stock a replacement WITHOUT rotor and cap (how would the guys who assembled it know whether they were selling it with a cap on it or not?). I mean, every distributor actually installed on the production line had a rotor and cap, obviously
I agree, they did some odd things like the part number cast into a part not being the part number in the parts book.

I think on the assy line the parts would have had codes etc.

In the parts department...

You could order a replacement dist or a dist ready to run.

There are a few other parts that are like that, I think the alternator could be ordered with or without a pulley (IIRC)