It didn't come in a Shimano box, but I guess someone like Ribble is probably getting them wholesale in different packaging from a consumer. It still had some grease on the axle so I'd guess it was fitted/removed from a stock bike, but can't see any marks/wear.
I bought a saddle at a massive discount, it failed within 6 months and warranty has proven almost impossible as I’m having to deal with Ribble themselves and their warranty department is not well set up.
Good to hear, may get one myself at that price.