A 9 mm Parabellum cartridge (a pretty scarce one) from Svenska Metallverken with a similar headstamp as the left one (except for “9mm” instead of “7x57”) was used on a contract to Chile in 1966. So the 7x57 could be a part of the same contract (?). I don’t know how close cooperation there was between Norma and SM, I would rather guess they were competitors… SM bought 50% of the shares in Norma in 1965 and eventually transferred it’s ammunition production to Norma, but as the new Norma factory in Åmotfors was not opened until 1967, it is not unlikey that SM finished the South American contract in 1966 in Västerås and then moved it’s ammunition activity to Åmotfors in 1967. 1965 is the last headstamp year on 9mmP and 7,62x51 form SM (026), by the way.
I have never seen the 1…1-code on a 7x57, but the same headstamp format was used on .30-06 by the Norwegian Norma factory in Oslo (“7,62mm” instead of “7x57”). At the RANO headstamps, which have similar codes, there are indications that the first (left) digit could have something to do with the case material (brass hardness). But the exact meaning of these codes are unfortunately not common knowlede here in Scandinavia either.
The codes that Rene shows, starts with 1…1 and run all the way up to 3…5 on .30-06. It is almost certain that these figures are case lot numbers. It is suggsted that 1…1 dates from the early 1960’s. According to my registrations, the boxes were undated until 1968, when they had reached case lot number 1…9. A box with case lot number 3…5 is dated 1977.