Also very useful info, as this is the earliest serial number yet reported for the second style trigger guard. Serial numbers 1192 and 1550 have the first style guard.
Looking at the list of serial numbers acquired from this thread and from some other sources, out of 18 pistols, 12 were calibre .177 and 6 were .22. I know this is not exactly representative, but this is a surprisingly high proportion of .22 pistols considering how rare they are supposed to be.