There is no question that the Black & Gold Salmon fly is the sole creation of Dan O'Fee of Rasharkin, County Antrim. Pictured below is one of his flies which came from the "Henderson Collection" and is dated 1887. With the supporting provenance there is no need to question the origins of this Irish fly, but with Farlow's Gold Baron, which appears in the Pattern Book, who is copying who, as these flies share very similar characteristics. Almost identical.
Particular Irish characteristics is the way the Indian Crow feather sits underneath the topping and the use of double gut which is not only attributed to Rogan patterns. This method seems to be widely used by Irish tiers including Enright of Castleconnell, Rogan, O'Fee, etc.
O'Fee was described as Ireland's champion fly-tier in the last quarter of the 19yj Century and he could be induced to produce local patterns for fishing on the River Bann and Lough Neagh. The Black & Gold had produced 14 Salmon to one lady angler, which appeared stitched to her fly book.
Kelson credits O'Fee with the tying in his book, the Salmon Fly, 1895, and the details of the pattern are totally consistent with the example above, save for the topping and Indian Crow.
The Gold Baron detailed in Farlow's pattern book is identical to O'Fee's pattern but with a different name applied. The Baron is regarded as a Kelson pattern. Also interesting to note that the release of Kelson's Fourth Series of the Black in Gold follows in 1902, some 7 years after first appearing in his book and 15 years following the creation of the patterns.
Two Hardy examples of the Black & Gold fly but both different. Not sure where the introduction of additional silk came in at the but and first section.
But they seem to follow O'Fee's general pattern.
Below is another pattern which again has similar characteristics, the Bourchier's Fancy, which may have been inspired by the pattern being featured.