Schema prep for migrating from SBS2008 to 2008 Standard NOT R2

Question

We have a small company with SBS2008, a file server with 2008 Standard, and a terminal server with 2008 Standard. We want to decommission the SBS2008 and DCPROMO the file server. I know we have to upgrade the schema from SBS2008 to a 2008 R2 migration, but is it needed if we're migrating to 2008 Standard?

Thanks in advance!