I bought one for my old Lenovo. It fit and worked fine, but some of the FN keys were marked a little different. It had the same part number though.
Almost for each laptop model, there are at least a few genuine keyboard suppliers (manufacturers). Layout and dimensions are the same, construction is not. As of those few replacement keyboards I have bought on ebay, they were genuine stuff.
You're better off buying a second hand one in good shape.
Totally disagree. If you receive some crap, just request your money back.