[Series 1 240z with out vented hatch]

You have it backwards. The early steering wheels have solid spokes, whereas the later wheels have holes. The steering wheel in your car in your car is original.

 

There was nothing transitional about the late series one cars. They ALL had the same steering wheels, hatch vents, and C pillar emblems.

rturbo 930: I stand corrected. Typed my original response from an airplane late at night and got it backwards.  Yes, early cars had solid spokes.  My 12/70 has holes.  There you go.

[Got a 240z and i need all the advice i can get!]

I am about 70% done of my first restoration ever.  Best advice I can give you (other than getting the Factory Manual for your year as has been already suggested):  Pick a project to start with, research that particular project extensively on the internet, and finish that project before starting the next one.  For example, right now I am replacing the stock rear suspension.  I spent a considerable amount of time researching the options and have resisted the urge to start something else (while I wait for suspension parts, for example) until I finish that job.

[Series 1 240z with out vented hatch]

For what it's worth, my 12/70 240z has the rear hatch vents. From what I understand though, it was around this time that they were switching over from series 1 to 2 and some cars got early parts, others didn't. My car could have been from the first week of December and yours from the last week, maybe that would have been enough time for the change?

 

I'm 15981, by the way.

I have a 12/70.  It has the hatch vents.  I think ryant67 is right in that these were "transitional".  For example, mine has the steering wheel with indentations in the spokes, rather than the one with the holes like earlier ones.