The bottom line of this story is - get a letter.
There has been a lot of discussion, back and forth, about what constitutes a "real"
4-inch post-WW2 K-32 . Some feel that a gun would only be "real" if the barrel
was originally made as a 4-inch barrel. There is no way to really know this, of course.
This argument is suggesting that the factory did ship some 4-inch K-32s, but the
barrels were first cut down, by the factory, from 6" barrels. This presumably is meant
to explain why the roll markings on the 4-inch barrels sometimes appear to be a bit
too far forward.
As far as I am concerned, this is not a valid line of reasoning. The only thing that is
important is - how was the gun originally shipped ? A 4-inch factory barrel is a 4-inch
factory barrel, regardless of how it came to be that length.
Furthermore, I think its highly unlikely that the factory would have made up forging
dies for a very small quantity of 4-inch barrels. It would be much more efficient to
simply cut some longer barrels to the shorter length.
The positioning of the roll markings is irrelevant. That is only a function of how the
machine was set up. I don't think there is any meaning to minor variations in their
positioning.
More than likely, unless a gun was a special order for some very important client,
the records will only indicate how the gun was shipped. There will be no information
about how a barrel came to be a particular length.
Your serial number is very close to some known 4-inch K-32's, as David suggests.
I own K685XX, which letters as a 4-inch K-32, with a Patridge front sight blade.
That should be the correct sight blade for these early K-32's .
In an earlier thread, perhaps referenced above, a 4-inch K-32 that did look "right"
lettered as being shipped with a 6-inch barrel.
Without a letter, one never knows.
Regards, Mike Priwer