Building a Laptop Barebone

the basic difference between OEM and Retail versions of a hardware (or software) is that the former comes as a part of a full working computer system with OS whereas the latter comes as boxed seperately to be installed in a Computer system.
So legally you cannot buy an OEM part on its own. It has to be part of a system. Thats why its cheaper. Computer producers purchase OEM parts and put them together to sell as PC's. Some sellers go around this limitation by packing another cheap computer part in the same package. If you buy several items all at once high street shops will sell you OEM parts. Like MoBo, CPU, Op. system etc.
In your case the first processor looks genuine, the second one doesnot have any marks or signs that I can see in the photo. It looks like a 3red party production rather than intel. Most probably you have already purchased what you chose, but if you have not i would go for the first link. regards.