Okay, so I went and looked up that Marcel Berthet held the World Hour Record in 1907 and again in 1913. I note that the model number of the pedals in question is "23," and wonder if that could therefore indicate the year of introduction to the market.
I'm curious about how many variants there are to these things. I know that there is a line drawing on Dale's site of what appears to be a VERY early version of these, the most wonderful pedals ever made.
I know that I have two different variants. the ones I got a couple of years ago from a bike shop's junk pile have round hollow areas where they thread into the cranks and two wrench flats. The set I got this week, NOS but without box (alas!) have allen-key fittings and hexagonal areas for wrenches to fit.
I seem to recall a discussion of these on the old list, but cannot find any of the material in my 'puter, so perhaps the discussion was prior to July 1, 1999. Among other things, one criticism is that the spindles were not as strong as one could wish, and would have been better had they been chrome-moly. At any rate, if anyone has any information they wish to contribute, lemme know. I'm thinking of writing something about them, and while I'll mostly focus on how well they work, it would be nice to have a tad more history to draw upon.