No problem, I welcome scepticism.I shared it to be honest, until I had the chance to examine it thoroughly. I'm pretty sure it left the factory this way and Keith Bayliss also handled it at length and said that he thought it was probably genuine. John Griffiths' 'pathway' to its authenticity is:
This is my favoured interpretation: The frame could have been one of the 800 or so that were made in 1952 and it is possible that although they were serial numbered they were not immediately stamped with any model number. In late 1952 some of these frames were taken randomly and stamped with LP52 to produce a small number of pistols for sale in 1952. By the beginning of 1953 any of the frames that had not been stamped with a model number would have been stamped LP53 and absorbed into the production run for that year.
However it is possible that a few of these early frames that had aleady been stamped LP52 did not manage to get made up before the end of 1952 deadline, and so rather than overstamp them they were mothballed. This scenario fits in with John Walters recollection of being told by Peter Hoffmann of Walther that the earliest guns were not marked 'LP 53', but that the designation was added once they attained a measure of success.
If at a later date, perhaps at a time when production was having difficulty keeping up with high demand, some of these mothballed frames may have been called into service and made up with newer parts. The LP52 stamp mark would have been left as it was, assuming that no one would probably notice, or care.
This would explain why the serial number of this LP52 pistol is later than that of the early LP53 pistol of serial number 1345, why it has a mixture of early and later features and yet has a clearly factory stamped LP52 mark.