Nice wasp Iain
No idea what it means, but it does look very nicely executed.
Should be able to post my flex test over the weekend, so it would be interesting to see if the flex matches the Clauberg.
I can't see any sign of a residual ricasso on your pictures, but it does look as though it has been sharpened pretty aggressively at some point so I'm not sure that means anything. The one difference I can see is the depth of the fuller, but that may simply mean that this blade has not been mistreated as much as some of the others. In fact I'm wondering if this repeated sharpening might also be the cause of the shallow and wandering shape of the fullers on some of these old blades - on the other hand they might have been made that way
