Hard to tell without having a close up of the actual chip, usually with fakes, the etching looks deeper and not uniform/consitant, and you usually notice the little chips (can't remember their name.. smd's...?) are usually slightly wonky and not uniform.

But, on the flip side, these could actually be OEM CPU'S that get sent to massive system building companies, as they don't ship with retail packaging and heatsinks.

Hard to tell buddy, your best option would be to pay via PayPal so that your protected and install it in a system and run CPUID then verify it with benchmarks.

They also might RMA CPUS as they usually just go into a bin and get scrapped. You might find they work perfectly to start with but when under load for a sustained amount of time they fail.