Sandvik is a Swedish firm known for high quality saws and tools. I found an incorporation in Minnesota dated 12/9/1929 and a revocation of the business in 1936.
Sandvik advertised that they had offices in New York and Minneapolis in 1930 (in addition to many other worldwide locations).
My educated guess would be that the pan was made sometime in the early 1930s, maybe as early as late 1929.
Sandvik seemed to work with Western Importing for the cast iron goods, I've attached a picture of the rosette iron booklet with both names on it.
As far as the molders mark, I call it a fish. It is found on all of the Sandvik Saw & Tool plett pans. I'm not aware of that mark being found on any Griswold products, but it is found on other Western Importing Products.
The pan is not scarce, but not common, you can generally find one on eBay fairly often. Value? I'm not certain, but I think $60-80. It is a nicely made pan.
I no longer believe that it is a Griswold product. It is of the same form as the Griswold, Alfred Andresen and early WICO plett pans, but it is smaller in all aspects and lighter than any of the others.
The fish mark is found on later Alfred Andresen Kornukopia pans and the 975 WICO base with a flat shank rest. None of these are marked as Griswold and are smaller than the Griswold products. An Andresen Kornukopia with the fish will not fit a Griswold marked 975 base, while the early Andresen pans will. An early Andresen Kornukopia pan will not fit a 975 fish marked WICO base, the pan is too big. Same for the 2992 marked skiver pan (although I have not found the fish mark on that pan). I've attached a couple pictures.
The change in the WICO cast iron seems to be related to the ousting of Alfred in 1912-13. They appeared to use Griswold for a while, but I suspect, to save money switched to another vendor sometime either just before, or more likely after WWI.
I've attached a picture of the WICO marked waffle iron with Griswold pattern numbers. No fish mark, but it is smaller than the Andresen version and will only properly fit a non-Griswold marked 975, flat shank rest base, some with the fish mark, some with other vendor markings.
More information than you ever wanted, but that's the world according to Tom. :)