This is such a beautiful pick! It is suspected to be the first printed guitar picks. I originally thought that it was from the 1920's, (maybe 1926) but a reference in a book (mentioned below) sites that the RWB trademark was used, 'even as late as 1912'.
Howard Eugene Wurlitzer was born in 1871. He joined his father’s (Franz Rudolph Wurlitzer) company the ‘Rudolph Wurlitzer Company’ in 1889 and served as president from 1912 until 1927 and as its chairman from 1927 to 1928.
RWB stands for Rudolf Wurlitzer and Brother. Rudolf's brother, Franz Anton, was a partner in the company from 1862 to 1890.
While the company was mainly involved in harps, they later produced a guitar under the brandname ‘Howard’ (1896-1920s) so this pick is dated from that era.
There is a really good book called, 'Wurlitzer of Cincinnati: The Name That Means Music to Millions' by Mark Palkovic, which gives the whole Wurlitzer story, telling how the company started from a $700 investment by Rudolf Wurlitzer, to become a well-known brand all over the world.
Why PICK A? The company gave their harps model names such as Style A, Style B etc., so Pick A followed this tradition.
The tiny writing at the bottom reads:
THE W & H CO. NEWARK. N.J.
There is also a good website on the Wurlitzer Family Graves here: https://mechanicalmusicpress.com/history/articles/w_graves.htm