Bob, thanks for the offer! PM sent!
Yeah, the whole "bumper hole" thing...............the only valuable lesson I learned on that one is NOT to post pic's of my goof-ups.

These guys around here never let you live down something like that.
Now, as for the thing sticking out of the block. That is indeed the oil filter. The reason I believe it has the two small towers sticking out of it is for the oil lines going to the remote oil filter. As far as I know, Datsun NEVER offered this as a factory or dealer installed option. K&N and a few other manufacturers have these remote oil filter kits and I've installed quite a few of them in my time. Without an actual oil COOLER, the only benifit from a remote oil filter set up is that you gain an extra quart of oil, and the filter is easier to get to. You may be right about it being a light. But if it is, it's the wrong shape and in the wrong location (not by far though.)
There are several more things with this kit that aren't correct, but it's still a good kit. The battery is turned the wrong way. Interior isn't perfect, wrong radio, choke, and E-brake set up, etc. But it's close enough. Actually, my biggest gripe (other than the high stance) of this kit is the lack of factory wheels. The rally wheels are all you get, and they are chrome instead of the polished aluminum that the original mags were.
Here's a pic of a pretty original 240Z engine bay. You can tell it's a 240 and not a 260 becaue of the rounded tops on the carbs. The 260 is almost exactly the same but has "flat top" carbs. Notice the location of the engine bay light on the passenger fender. Again, the kit piece is totally wrong to be a light, but you may very well be correct when you said that's what Revell ment it to be.
BTW

But the blue spark plug wires are also not factory. They look like the old Laserlight plugs that I installed on a couple of Z cars I had long ago. Pretty cool stuff. They are actually a translucent blue and at night with the engine running and the hood popped you can see the sparks traveling from the distributer to the plugs.
Hermon