Yes they do Wayne. Go over to photo.net and type "hexanon focus" into the search engine. The majority experiance is that Hexanon-M lenses work fine on Leica M bodies. I have used my 28mm on my 3 M bodies and so far no focus problems at all. I used a 90mm for a year - no problems, a 35mm for 2 weeks also with no problems. All anecdotal but there are a lot of anecdotes that point in the same direction.
You are correct about the sample variance. As I recall it had to do with sample variance in both the Konica lenses and the Leica bodies, not just Konica. In everyday practical shooting most people have had no problems whatsoever.
The really sad thing is that these Konica lenses are no longer made. The good news is that there are 5 Hexanons on sale at the auction site right now! 😀 Take a look at the 35/2 that Martin is considering. Is that a beaut or what? 😎