Vivitar lens from Nikkormat?

I'm looking at a Vivitar 75-300 zoom lens on Ebay. It was used on a Nikkormat camera, what year I have no idea. I have a Nikon D40 and while I know the zoom won't auto focus or set the aperture, that's no biggie because I did all that stuff by hand for 35 years before I got the D40. Knowing the old Nikon F lenses can't be used on my camera, I'm concerned whether or not the lens mount is the same between the Nikon and Nikkormat. Supposedly the Vivitar lens is AI. If it helps any, the serial number indicates it's an older Kino made lens. Thanks.