I've got a headache from looking on eBay - seems you get one totally misinformed seller - and others use that info to determine what they have!
Today, I've seen several top clamp greist attachment sets (with cardboard liner, so later ones) listed as SINGER Late 1800's. One is even says "Standard" and the sellers says its a standard Singer set . . . At least I hope most people with Singers would be smart enough to know that a top clamp set for Standard won't fit their machine.