Update:
I did a focus test on film with the with the 28mm on land. I'm processing the film now.
I got a simple Nikonos V NOS ring set with grease on E-bay. Indeed it only has a few of the total number of o-rings needed.
I have a 35mm lens on the way, in case the 28mm turns out to be to difficult to focus on land.
No word from Nikon customer service so far.
I'll probably only replace the o-rings that are easy to replace, for example, those around the take-up knob and the wind knob and the cover latch. I'll be using the camera mostly around a pool or in shallow fresh water. The closest salt water is over 300 miles away.
What I might do is to measure each o-ring and then re-grease the old ones (not much grease, if any left on my camera) and order a second set. It looks like I may need to order the o-rings in multiples (50 or 100) so I may have extra.