950-s refers to the weight of the silver. Kuyeda is a Japanese silversmith. I've linked to a seller who has butter pats with that mark.

Google around "Kuyeda silver" and you'll find a number of items for sale.

Here is a link that might be useful: Butter pats

950 refers to the purity (silver content) rather than the weight. 95% pure silver, 5% other metal(s), usually copper.

I hit the submit button too soon! Here is a link (at the bottom of the page) showing where it is/was a trendy jewelery shop in Tokyo.

Here is a link that might be useful: K Uyeda

I believe the 950 refers to the purity....that is 950 parts out of a 1000 silver.
Hard to tell what they are worth without seeing a picture or knowing the size, but Kuyeda made some fairly high end stuff....and I would think having 12 sterling or better place card holders would be very neat!
Linda C

Thanks everyone for the replies. I though it was silver, appreciate the confirmation. I'd found the sites mentioned, I just couldn't find anything on these. Thanks everyone, I'll keep looking.