I have received a Zorki 1c with serial number on the back. The serial number is engraved upright instead of italic. Just like the very first Zenit cameras. I have never seen this on a Zorki 1 before. Maybe this is a factory error? Or are there more with non italic engraved serial numbers?
Hi Ulrich, In Albino Pegorari's and Claudio Asquini's little booklet of Zorki classifications and characteristics there are two groups of Zorki which they classify as "Zorki 1 C1 & 1 C1A" and "Zorki 1 D1 & D1A" which have the serial numbers in upright figures on the back.
These are listed as 1951 - 1953 and serial numbers (approximately) N. 138,000 to 425,000 (maybe only some unknown amount of cameras in the middle of these series have the upright figures ... the exact serial numbers of this type of engraving is not specified). Before and after have italic numbers. These cameras have the Cyrillic script and also Roman English logo engraving (usually referred to as "Zorki-Zorki" or "Export engraving".
I'm not sure from personal experience, but mostly their books seem to be correct in the details and are learned from their own personal collecting experience.
the number range you posted matches, mine has serial number 426xxx. I have had around 6 Zorki 1c in this number range but I have never seen an upright engraved serial number before.