They're good, but I'm afraid they're not that rare. Most of the photos have been published in The Three Stooges Calendar that I've kept a current copy of hanging on my wall since 1996. I have most of those scans myself, because each year after I take down the calendar, I'll scan the images before tossing the calendar.
Now, I suppose, though, the rariety of the images is that they do not have the goofy borders and truncated images that one gets with a calendar scan. Thanks for posting them.