The Yottamark to check is the one that you finally receive in the delivery as it is unlikely you will be getting the one that is shown in the picture. It is unclear from the Intel webpage whether they would cover the consumer line of NICs with the Yottamark verification.
I just pointed it out that since the first vendor picture didn't have any Yottamark (maybe they removed it for security reasons???) while the second one did. I assume the Yottamark sticker would somehow be associated to the unique MAC address(es) and/or serial number of the NIC and an inventory list of actual NICs that were shipped out by Intel legitimately; hence the need to check online. So a counterfeit NIC manufacturer which relies on rejected and/or stolen chips (yes, I read numerous stories over the years of truck delivery of Intel chips being stolen in Malaysia) would not be able to pass the Yottamark test.
But of course, there could also be counterfeit Yottamarks just like in the 1990s there were counterfeit Certificate of Authencity hologram slapped onto counterfeit MS-DOS and MS Windows shrink-wrapped boxes with diskettes that also looked like the real thing; and the pirate copies were sold at full retail price.