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I heard back from another retired Honda person on this question about the JIS vs. ISO vs. Phillips question.
Apparently the Honda screws with the single dot on them are the ones that have the newer ISO thread combination, and the older screws with the JIS thread combination have no dot on them. This is reported here:


As far as any of us know the shape of the "+" recess in the head of the screws did not change when they made the change to ISO threads beginning in 1967.
The friend who is the most knowledgeable of the three of us, thinks that all of the Honda screws have the JIS variation of the Phillips shape in the screw heads.


This friend worked on a problem situation years ago where removing some Honda screws was very difficult out in the field, and the best solution they found was this Snap-on driver bit. These Phillips "ACR" driver bits completely solved the problem they were having.


The picture on this web page shows you the "teeth" they put on these Snap-on "ACR" driver bits, and this link is for the #1 size driver bit.


Thinking back on things that happened using the Honda screws, I remember having to grind the sharp point off of Phillips screw drivers to get them to fit better in the Honda screws, which helps support the idea that the screws are in fact JIS, and not a true Phillips shaped recess.

I have a new set of Kowa brand "T" handle screw drivers and sockets. They are the ones often used in Japanese motorcycle maintenance, and I assume that they are whatever is used in Japan (JIS or Phillips?). When you compare the Kowa screwdriver tips with nice Snap-on screwdriver tips there is not much difference. I will take a closer look and get some measurements and pictures of them.
tom jobe...
PS A little later, a close look at the Kowa screwdrivers and some nice old Snap-on Phillips screwdrivers shows no functional difference. The Kowa tools being new seem to "grab" the Honda screws a little better, but only because the old Snap-on tools are worn a bit smoother from use.

I'm still amazed at how well the new Pozidriv screwdriver works in the old Tektronix Posidriv screws!