Hello:
Requesting your kind assistance to identify origin of these items and whether the markings confirm silver plate. Searching on this particular (silver plate) forum yielded zero results for "MK4" markings. One result on the general site yielded a question regarding the "MK4" marking, posted in 2010, but received no reply and "error" on link to picture. Additonally, on the general site, I did find "MK" but that was under "World Marks - Russian Hallmarks", which I believe refer to solid silver (not silver plate), so I'm not sure if there's any relation to my "MK4" marking.
Back of tray pictures (one close up one non-close up) show "MK4" markings in addition to a "K" marking. You will also note (in the non-close up back of tray picture) that an old price sticker is showing with the word "BERIOZKA". I believe it refers to shops set up in Soviet Russia (1960s-1990s) that were designated for visitors, dignitaries, etc., to shop at.
The tray came with 6 goblets whose stems/feet have a kind of see-through floral filigree-type detail. None of the goblets have the "MK4" markings that the tray has. Four goblets have what looks like a "7" marking, one goblet has what looks like a "2" and one goblet bears no marking at all, as showing in the pictures. The inside of the goblets have a light gold coloring, in contrast with their outer parts and the tray, which are silver-toned.
I have carefully read through this site's guidelines for posting and uploading pictures and I believe I have respected them. Please do let me know if not so that I can remedy any issues.
Thanks in advance for your time and any info you can send my way,
Margareta
https://postimg.cc/gallery/1hty4pfvg/