James,
I have a similar post card, made by same publisher, but titled differently ("Boxing" Series). I know I've seen a check list for them, but I can't find it right now. I have no proof, but I've always felt they were of the period (c 1910-15). They show up on ebay every once in a while, and go for about the price you paid.
Sorry, not much, but a great Attell !!!!
bnrngpc.jpg
BTW, Nelson has a gloss finish