I think they are supported, from 10-9 to 10-10 there are about 15 new pci ids (i use a whitelist for fglrx). Btw. since the german ct magazin reported that the opengl windows performance is really bad amd responded immediately with a hotfix driver.
http://support.amd.com/us/kbarticles...10aHotfix.aspx
I reported excactly the same when i compared ungine heaven benchmarks win vs linux and NOTHING happened. But when ct magazine tests it and gets the same result then amd is in a hurry to fix it. I hate it...