Otto, I don't know how the Strempel / Eblen / Göring / 7x75R v.Hofe SE rifle is marked, as I have only seen photos of the engravings and inlays. Here is a photo of that rifle published in H-J Fritze's "Suhl" book, probably from a Suhl archive.
IMHO the lack of caliber designation on your barrel is a further indication, like the blank lumps, that your rifle was lifted from a shop in 1945 in an unfinished state. The German 1940 proof law required the real cartridge designation to be marked on a gun before it was released to the public. As "7x75R vom Hofe Super Express" is a bit long to be stamped on the under barrel flat, it was probably intended to have this long and novel monicker engraved on one of the upper barrel flats or the rib, together with the "maker/retailer" name. Evidently your barrel never made it to an engraver after proof, so it lacks the usual inscriptions and decorations.
Loads were not to be marked after 1940 any more. While before a maker could specify a reduced-pressure load under the old law, the 1940 law required any gun to be proofed for the highest-pressure factory load then available. At the same time these pressures were set as "maximum pressure" for a given chambering. Noone was allowed to load cartridges exceeding this max pressure.
