Well they are in fact pretty rare to a certain degree, some more so than others based on characteristics. Often what you see are the same ones that are being "recycled" if you will. Most of us that collect early pieces have owned one or more that currently may reside in another collector's stable. That guy decides to let one go, and it appears a "new" example has surfaced.

Occasionally a "new" one does show up, no doubt, but it really isn't that often.

I don't know what the ratio is, thong link to thong hole, but I would say more knives were made in 1944-45. Again, it depends on when the actual switch took place, AND, the fact that standardization helped improve production.

I have to reread Gaddis, but I think he goes over some order numbers during WWII.