I can't wait to see the end result of your efforts, Alan!
Apologies for geeking out: Notice also on the previous photo you posted that the other fender has a "Fairlady Z" badge and no headlight covers originally, and then finally (at the Racing Show) what appears to be a "DATSUN" badge, covered headlight, and if i'm not mistaken, a tiny circle in the front of the scoop, indicating the possible presence of a defogger. And yet at this point, not yet having the front-facing headlight change. Also of note, is what appears to be clear lenses for the running lights. It's great to see how the development progressed.
As to the left fender, with possible accident repair vs. intentional omission: I'd venture to say that both are possible. Perhaps the left side marker was omitted intentionally at one point, either before of after a possible fender-bender, just to see what it was like. With the dual-bulb driving light, One could easily rewire it to use one bulb for running light, and the second one for turn signal. (I'll tip my hand here a little bit, and mention the possibility that some Works harnesses may have used the 4-pin connector for the 2-bulb driving lights instead of the 3-pin, even though only one bulb was wired up, leaving the parking light unwired. But perhaps I'm overthinking it.)