Wow, Intresting marks, have looked around my books and sites I know and have come up empty too. It could be a silverplater that bought un plated items and plated it themselves. This was not uncommon in the late 19th and early 20th century, and are one of the many unknown markings out there. I did go though a couple of sites and even looked into the unidentified. I will keep this mark in mind and when searching out marks I will keep my eyes peeled. I have a few items that I have still not be able to place. Or maybe someone else may know those marks or have better searching skill then I. Is it possible to see a pic of the item? Style may give clues, or at least help place a date.