That is one of the trade-offs of buying parts from eBay: no datasheet, no listed manufacturer, ultimately no responsibility. Maybe they are parts taken from the same factory that produces name-brand parts, but they can't advertise the exact origin, hence the killer price.
I bought a 50 pack of LEDs from eBay for $2 shipped, but I didn't expect, nor receive, a datasheet with a characteristic curve. For my little project, I didn't care, I just wanted cheap LEDs that got bright. Buying the same thing from Dig-key would have cost $10.