Just for completeness, the Nissan part number is 48750-E7705.

Installed the new switch and she's back to starting as she should.

As a note to others, there is a short video (Google) on how to go about replacing an ignition switch on an old Z. I found this was helpful.

So did you replace just the electrical part and save your keys?

Exactly....Still have both of the original pairs of keys...sentimental, I guess

So you used the original ignition switch hardware and just replaced the electrical piece that attaches to the harness?