Maker Mark Identification of Silver? Spoon - age?

Sure appear to be silver, but no markings other than the O on the reverse stem. It has that nice bright silver patina all over it. Usually, with small scratches, you can identify plated, but there are none.

Any idea as to the maker or the age of this spoon? What type of spoon is it? It measures about five inches long. Could it be a baby's spoon? Any help would be appreciated. Charles