I wonder if my ones are the real deal?
Don't worry, I buy similarly and have never had a problem (almost*).
These sellers buy in bulk, then use contract delivery, and eek out a profit where it would be unprofitable on an individual basis. In the absence of Maplin, Tandy, and the back-street electronics junk shops/hobby shops of my youth (there are still one or two about, but you have to be in the right part of the country), eBay is your best bet (RS, Farnell, Mouser etc have minimum orders and delivery charges which make the purchase of the odd capacitor or two totally uneconomic).
* Except the time a pot was advertised as "log" when actually it was reverse-log. The seller was adamant I was out of date and reverse-log is not a useful description, that I should have been aware of what the taper code meant, but gave me my money back anyway so I guess he lost the argument without admitting he lost the argument (and changed the listing - but still it doesn't say reverse-log when other sellers do).
He claimed to have sold hundreds, including to "professionals" without complaint, but I can't think for the life of me what mainstream use there is for a reverse-log pot, so I suspect people buying them simply haven't noticed their volume controls don't work very well. My opinion is that he has a batch of nearly-useless reverse-log pots and found a way to off-load them onto the unsuspecting.
That was close on the heels of a run-in I had with the seller of a disco light. The unit supplied was of lower specification than advertised, so of course the seller was responsible for return post but he refused to acknowledge that. I invoked eBay's returns process, and eBay issued a returns label (which might have been what the seller wanted to happen, but as I had never done it before it would have been helpful if the seller told me that). I left that seller negative feedback for what I viewed as potentially deliberate mis-selling, and he complained that as I had received a refund, I shouldn't have done!
Then there was a microphone which was absolute crap, and the seller disappeared. I could have invoked eBay's returns, but I was unaware of it back then.
Apart from that, over hundreds of purchases, my experience has been overwhelmingly positive.