It's hard for me to say, because it's a long time since I've handled one of this style. I think from memory, the 'bubble' protrusions were blown out from the body of the glass, not applied to the outside as a prunt. Also, I think the protuding 'bubbles' were in straight alignment, not offset.
I've got Designlasin in front of me, seems to agree with the alignment theory, but it'd help if I could read the language. :roll: