Yeah, the J. Springer Erben's Weipert 450 X 16 was an exception piece @ one time. It has some light exterior pitting and like you, I wish more info would have been provided. I asked for the proof marks & all I got was the Final 1910 Datastring. I don't think knowing that it was relined to 6,6X70R would have had any bearing on my purchase, but for some reason it appears to be devoid of any rework marks.

[Linked Image from thumbs2.imgbox.com]

Here is a Springer Hammer DR with Belgian pattern welded tubes, which is somewhat rare. Well, rate in the fact that they left the Belgian marks on the tubes. It seems that if Springer made one in-house, they sourced Liége for components, especially tubes. But if they sourced the mechanics in Vejprty / Weipert, then tubeset was sourced from Suhl.

Hochachtungsvoll,

Raimey
rse