Hello and welcome Rusty,
I too have a 1970 cb750 K0; but I don't have my numbers in front of me at the moment. It was manufactured November 1969, though. I love it. Bought it from a previous co-worker for next to nothing, and it being my first project has been an absolute God-send. It's not pretty, but the joy I get out of getting her to run has been great. I'm learning the mechanics of it all, but also learning a bit about myself too. If you've read "Zen and the Art of Motorcycle Maintenence" you'll know what I mean. The people here are great, tons of commeraderie, just good people.
Welcome again.
Prost!