Those markings all indicate the barrel blank manufacturer (subcontractor) in the Reich. My BBOTW copy is at home right now, so I can;t tell you which maker it was. Sorry. Not really important anyhow, as it's the Czecks who finished and proofed those post-war assembled tubes.
Basically ALL the Israeli K98's started as 7.92mm. The conversion to 7.62 was mostly an early 1960's job. Parts were stripped down, parkerized, mixed up and re-assembled as mixmaster 7.62 rifles with (usually) new beech furniture though sometimes the laminate stockes were retained.
The bolts on these 7.62's were jumbled and sometimes renumbered matching. No idea of the 8mm bolts were sometimes put into 7.62 refurbs but anything's possible as they DO interchange freely.