No, no chance of a date post September 1923 as that was when dating they began their wares. For the next 6 months or so a ledger number was paired with the date and there are 2 possibilities regarding stamping after that. Either there was a renovation at the Suhl proofhouse & they Suhl sent their wares to Z-M or Suhl used a ledger number. I hold strongly with the latter. The Star over H is either for tubes fabed at Haenel or for one of the mechanics at Haenel. It is possible that there were several Hengelhaupt mechanics employed at Haenel & the script H stamps are their liability stamp. For now I do not think they own the Star over H. Yeah, 7600 PSi sounds nice & I'd hold with 67mm or shorter. You can approach a 27 gram load as long as the pressure is checked.
Kind Regards,
Raimey
rse