Adding a DC 2003 R1

Hi,

My first Domain Controller is a Windows Server 2003 R2 SP2 x64. My second DC is a Windows Server 2000 SP4. I want to raise my Functionnal Forest and Domain level to 2003. So, I want to add an other DC and then kill de DC 2000. But my new DC will be a Windows Server 2003 R1 SP2. I am wondering if there is a problem because it’s not R2.

Actually:
Forest Functionnal Level : Windows 2000
Functionnal Domain Level : Windows 2000 Native

Thank you