The pictures of the black leather loop look identical to the black leather loop I bought from Apple with my S0. The short band does not have "assembled in china" engraved on it. I wish Apple still sold them in black. It's my favorite band, but the leather has started to wear after 3 years.
Just a a thought exercise on "how is this possible..."
1) They could be counterfeit; made in a different factory in (I assume) China with the same/similar tooling. This gets into trademark, patent, design violations.
2) They could be made in the same factory and a manager/owner just runs the shop for a few extra hours to make goods to be sold directly to consumers for more money than selling to Apple. I assume this would violate the contract with Apple.
3) They could be made in the same factory and a manager/owner just runs a few extra assembly lines to make goods to be sold directly to consumers instead of selling to Apple. Sort of "apple pays me to run 5 assembly lines, and I run a 6th just for myself and sell directly on eBay." I assume this would violate the contract with Apple.
4) They could be made in the same factory and these are QA rejects. There are most likely contractual obligations that rejects are to be destroyed / recycled. If so, then yes, that would be theft - Apple still owns the rejects and specifies what is supposed to happen to them. It's just a question of "is an employee stealing rejects from the factory or is the factory stealing rejects from Apple."
5) They could be made in the same factory on the same assembly line. Employees are just stuffing a few in their pockets and walking out with them. "5 for Apple, 1 for me. 5 for Apple, 1 for me". Theft.
6) They could be some form of customer return. I struggle to think of a good scenario where a 3rd party would have access to stock that was returned by a customer to Apple. You'd either have to get the returned item from the customer BEFORE they returned it to Apple (which would be completely legitimate - I'm free to sell my watch band to anyone and they can resell it) or get a returned item from Apple after it was returned (this would only be legitimate if Apple was selling returned product to a 3rd party after it was returned - which seems unlikely). Although, it is possible that Apple has partnered with a 3rd party to help handle/process returns and some returns "fall off of a truck".
7) The are Grey Market and because of taxes, exchange rates, etc it is profitable to buy legitimate products from Apple in China and then resell them internationally. It's possible, but I'd expect the price difference to be closer to 10%. This happens a lot with camera equipment - lenses are cheaper in Canada than in the USA, so you could go to Canada, buy it and save 20%. But (1) you're supposed to declare at the border that you bought something and pay an import tax (2) the warranty may only be good in Canada, so if you need it repaired you have to travel back into Canada.
Personally, based on the pictures that have small defects (small scuffs/scrapes, partially rubbed off engravings on the leather), I think #4 is most likely.