August,
As long as the information is the same there shouldn't be an issue with the MiCollab and AD databases. I just did this yesterday and the only ones that didn't want to perform an update were the ones that I had a different name, ie it was spelled wrong.
Keep in mind that the main pieces of information that it looks at is the first and last name, login ID, and Primary extension. The remainder of the information doesn't matter except that it will change it according to how AD has it within its directory.
Also don't forget to make sure that all of the profiles that you want to manage with AD have the Manage with IDS box checked within the MiCollab.
Thanks,
TE