Will a Nikon D80 meter work on a Pentax SMC K Lens?

I have a nice Pentax SMC (K-Mount) 50mm f1.2 all manual lens. I know they sell pretty much every adapter imaginable. And I do happen to have a Nikon D80 DSLR. I know I have to control the camera completely manually, but will the meter work with a K lens?

I doubt it. Check the D80's manual to be sure.

No. On nikon you need a d200, d7000 or better to get metering with all manual lenses

Another point, is the adapters…

If you use them, you will loose at least a few stops on that fast lens, making the f/1.2 pointless.

First issue, mount adapter for k-mount lenses to Nikon bodies exist but fall into two categories both not so good. The first are just manual adapter rings that fit between lens and body, they work but are too thick to allow the lens to focus to infinity, the second type have and optical lens element, permitting infinity focus but image quality ranges from mediocre to downright awful.

And for metering you would need a D200, D300, D700 or any of the pro series D1-2-3. And that would only be stop down.

Pick up a nice used 50/1.8 AF for under a hundred bucks and sell that 50/1.2 Pentax (you might get enough to buy a new SB-700 for your Nikon).