The fun thing about those is they were physically quad cores with one core disabled, which may or may not have been defective, so if you were lucky you could unlock it and get a bonus core for free.
Binning made the world weird.
Made it so sweet too. Buying a product that could become so much more (more frequency, more cores, more cache) at no extra cost was magical.
Got a 4 core machine that way dirt cheap. Bought (a phenom II BE I think) 2 core cpu which unlocked into a quad core.
Unlocking downgraded tech is one of the purest joys.
Unlocked a 6800gs video card back in the 8x agp days. Freaking sweet for a 16yo!