Very well could be. But there were the Keltt's & the Kelbers. Then the Kelber's split the sheet & there were 3 or more. Those are process marks in boring & finishing a tube/cutting a chamber. I would assume if a Script »WK« was on a tube that a Kelber, and not a Klett, worked on the tubes??

But either way, the marks are one of 2-3 families of tube makers.


Hochachtungsvoll,

Raimey
rse