Do I need to translate security on user profiles when migrating users intraforest
Domain Migration Administrator 7.x
In an intraforest migration to a native mode target domain, the user account is moved rather than copied. The target account receives a new SID, but the SID of the source account is added to the SID history attribute of the new account. However, the GUID of the account is retained. Therefore, you do not need to translate security for user profiles on Windows 2000 computers. However, you do need to translate security for user profiles on computers running Windows NT 4.
For more information, refer to Chapter 11 - Intraforest Migration, of the Microsoft Domain Migration Cookbook: