Hi cujob,
are there any numbers/letters stamped into one of the pair of uprights supporting the "shield" between the stuff down the bottom and the ring getter up the top? If so, these should help identify if it is Siemens and when it was made. If there's no stampings, then you should find the vital details etched into the glass somewhere [not always easy to see]. For this design of [Siemens] tube, the earlier ones used etched markings while the later ones used the stamped, internal markings.
The getter looks a little on the large size for a Siemens though the little reinforcing ridge [if I'm seeing it correctly] on the support for the getter is in the style of Siemens or Telefunken while Phillips/Amperex had a plain piece of metal there.
jules
jules