Bernard:
The original plate was introduced by the Model Flint Glass Co. of Findlay, Ohio in late 1890 or early 1891. There was an article in a Findlay newspaper on November 24, 1890 that gave mention of the mould being completed by Mr. Henry Coons of Arduser & Co., a mould factory. In April 1891, the plate appeared with the caption "The Finest Iron Mould Work ever Executed" in an ad in China, Glass and Lamps. (Ref. pp 121-3 of Findlay Glass by James Measell and Don Smith).
According to Identifying Pattern Glass Reproductions by Jenks, Luna and Reilly (pp 207-8), the first reproductions appeared in 1937 produced by New Martinsville Glass Company. by 1973, Indiana Glass Co. was producing a large plate from a new mould in many colours. In 1976, Mosser Glass, Cambridge, Ohio introduced yet another version.
There is a book out on the Indiana Glass Co. that may have more information but I do not have it in my library.