It was made by the Wm Rogers Co., it is called Anchor, Rogers, Anchor. cannot find anything about Roman Numeral XII or the Pat. date. Seems to fall 1865 or so.
The patent date of 'May 28/05' likely refers to a design style, type of plating or even the material the spoon is made from.
Stylistically, it dates to the first quarter of the 20thc.
The stamp 'ROGERS XII' would be the design inventory number.