Yes, when installing a WHQL, sure.I just go to control panel, right click the AMD install manager, select change and uninstall all AMD software.
Theoretically it should be enough.
However, this thread is about the beta?
For a beta, you must get rid of left-over stuff, like overdrive profiles and such, maybe some registry keys. I always remove driver as you say, but before reboot, I manaully delete AMD folder on C:\, and then remove AMD/ATI listings in the registry under the "SOFTWARE" sections of each main heading. Then I reboot. Not much more than a normal install, really, but I found it fixes issues with Overdrive when swapping cards, so now I do that each and every time I change drivers. ATIMAN and all that other stuff aren't needed, IMHO, unless perhaps you run full AMD rigs, which I do not.