There is an additional part to this deal. You can get $40 off ~any~ AMD board if purchased with one of the listed CPUs. Actually, as with the main deal, there are some unlisted CPUs for which the $40 off works, but only with a subset of motherboards.Once again you'd have to experiment with mixing & matching in your cart and see what happens.
I got the GIGABYTE GA-MA785GM-US2H, listed at Microcenter for $99.99, for $39.99. Price match with Newegg's $79.99 (Yes, Microcenter does that if you ask nicely) then $40 off with purchase of Phenom ii X2 560.
The Phenom did unlock to 4 cores, I just looked at the box the CPU came in and it is the "GM" as per 13gigatons comment above. I expect all Microcenter branches will have that line of CPUs.