Swiss Silver Naif & Cie, looking for any more informatio

[imckinnon]

I have a set of 6 teaspoons in a box. Inside the cover of the box there is a label, Naef & Cie Turbenthal. The only markings on the spoons are: KGB 90-18 and a circle.

I am reasonably sure the box and spoons go together. Though not positive as I got them from my mother.

Can anyone tell me any more informaton about these spoons or the maker?