You've pretty well summed up piece. I would expect that that the FK would be FM, to indicate that it was made by the Marcolin brothers, who moved from Murano to Sweden and opened a furnace there. The numbers are production numbers, which I can't help you with. If you Google Marcolin, FM, or FM Ronneby (Ronneby was the location), or FM Kontsglas, you'll find a wide variety of their products, often animals. You have quite a large pair.