Removing the first Domain Controller and introducing new 2012 domain controller

My question(s) is related to removing the first domain controller (Server 2003) created.  Our Forest is at 2003 level, and includes only a single domain (2003) level.

I don't believe we are using EFS or ADAM but want to verify I tested correctly with "cipher" command.

Any other steps I need to take since it is the first domain controller? 

I did backup the private certificate even though it expired, and as stated above don't believe we use EFS.

Any gotchas I need to consider in introducing a 2012 domain controller?

Thanks

Minoo Jalal