Hello Suomoo For your cup the following information: The name really means "Schlapperiz" in today's spelling Schlapperizi. This family are citizens of St. Gallen. They had previously owned in Lindau. The maker's mark "AIR" is probably the Lindauer goldsmith "Rüel. It was ab...
the mark and the shape of the spoon demonstrate herisau (Switzerland).
I have even spoons of this city.
The marks of Herisau you can find also in:
"Weltliches Silber 2, Catalog of Switzerland. Landesmuseum" p. 65 ff
I can not say with certainty what country the brand comes from. But I have several times in cups and plates in churches in Eastern Switzerland documented.
I know the Mark- it is very common to find. It is only of objects from pewter to find. I do not believe that the audit was serious. Sorry, but I am 100% sure.