Far out - the drive pin that is, maybe 2" shaft-center to pin-center?
I just saw a similar-looking 22 tooth version; I almost missed the offset of the drive pin, even more pronounced on a smaller wheel.
So there appears to be 28, 26, and 22 tooth versions, (perhaps even a 24 somewhere).
Sometimes on these parts, not only is the crank pin different (than most), the shaft and threads may be oversized diameter. So, for parts staging purposes, these parts go into the "special fit" box; the special sprocket needs to go with special crank, and with the special cones (oversized threads). I have found that the special oversized cones that eventually wear-out are the hardest of these groups to acquire, usually 1 or 2 short of the number of cranks and sprockets that one might have; "a boon to repair men" indeed.