FWIW, Amazon has had a bunch of counterfeit parts on sale recently. Motorcraft spark plugs and filters are a couple I have read about. ebay may also have the same thing.
I think I would be careful and inspect closely any auto parts etc from both sites.
I have ordered Stens and other parts vendors, and have used O'Reilly house brand with no problems. For the service of small engines, I think the house brand from larger auto parts stores should do the job without problem. Just do a cross reference, and look at the visual quality of their product, buy if you like, decline if not.
tom