etched by someone else

Certainly a possibility, and I can’t find any sources supporting or contradicting this. It looks certainly like an odd choice of symbols for Henckels. One thing sticks out to me, though: the Friodur logo is on what is typically the back side. All decorated blades I know (contemporary examples include Puma, Rolli, Böker, Filarmónica, earlier examples are Wade & Butcher, Frederick Reynolds, etc) are etched/inlaid on the other side, including later decorated Friodur blades.

So I think it likely that the Friodur logo wasn’t meant to be the main decoration. This wouldn’t necessarily mean that the masonic symbols were, though. I’m wondering whether this was a blade meant to be personalised.

My father (1912) told me what a big deal it was when stainless became available in items used by the general public.

Oh, I can imagine! I think it took a while before it became a true replacement for carbon steel, though. Stainless steel welding was a problem for a long time, and early stainless blades wouldn’t hold an edge until cryogenic hardening (Friodur) was discovered.

I still have no clue what soap I’ll use.

Same! I am incapable of making a decision right now 😅