Pins for $1 on ebay are definitely not pins that Disney officially released. But, they are often made with the exact same molds and and at the exact same factories as the ones Disney authorized.
What happens is that Disney gives a factory an order for pins. Say, LE 3,500 pins. After the official run of 3,500 pins, the molds are supposed to be destroyed. They're not. Instead, the factory runs off another batch of them - maybe 1,000 more, maybe 10,000 more. Those are "scrappers." They have the same copyright, date stamp and all that because they're made from the same mold. But they're technically not official.
Literally the only way to know 100% that the pin you're getting is "authentic" is to buy it from Disney at full retail price. Everything else is subject to interpretation.
Is it "wrong" to buy the $1 pins since they're not technically from Disney? Well, that's up to you. I've bought some in the past for trading on lanyards because what's on lanyards (and thus what I'm getting back) is most likely not authentic anyway. To me, it's not a huge deal but for those wanting specific, limited edition pins it does degrade the value. But I don't have a pin collection for it's resale value.
Check their feedback to ensure you get your order - NOT to ensure they're "authentic." Because there is no way you can sell an item that has a minimum price of $8.95 for $1 and make money unless they're from overruns. Don't use the feedback as "proof" they're technically officially released.