As long as this game engine doesn't have an aversion to the Core 2 lacking an onboard memory controller, the first Black Ops didn't like the dual core versions of the Core2, stuttering was the result. Nobody knows, wait for it to come out. Also, I'm not sure how well the GTX 280s would handle tesselation. Nobody knows if Black Ops 2 will actually use tessellation. Tessellation is *THE BEST* feature of DX11 and really makes DX11 great, too bad most devs don't use it in their supposedly DX11 games.
Check out the comparison screenshots on this page if you don't know what tessellation is:
Yea, short of tessellation (which probably wont be in the game anyway) I see no problem with your graphics cards. PCDev did say that requirements have been lowered and some CPU problems have been fixed. Probably thanks to finally dropping WinXP and DX9 support which was old even in 2010. It seems like the problems are fixed and your CPU should do great. Should being the keyword.