NT4 (Help)

Ok im moving from NT4 to 2003 AD, i have asked a few questions and they have been answered so thanks to everyone for that.

I am pre nt4 im only 25, so this is my question once this is answered i can then plan the upgrade.

I only have one PCD no BDC, so all logon details and so on are held on the PCD, so what i plan to do is add a 2003 to the nt4 domain as server then run dcpromo to make it a BDC then run dcpromo again to make it the PDC and demote the nt4 PDC to BDC now the question is will the logon information on the old nt4 PDC be copied to the new 2003 DC.

I want to know this because i plan to upgrade the current NT4 PDC to 2003 put don’t want any down time because of the upgrade?

Thanks