Hello Gaspare, there are some really crazy items around that are totally period. Saying this I cannot decide what to think about this butter knife.The font of the letters is not common for such markings. If there is nowhere a comparable one I personally would hesitate to think it is period but would not damage it but wait until perhaps something does surface.
Once have had this sauce boat - but I did know the origin what was doubtless.
Regards,

SS LAZARETT M�NCHEN-DACHAU.JPG (50.23 KB, 88 downloads)
wotan, gd.c-b#105

"Never look for sqare eggs" as a late owner of an original FHH-dagger used to say.