I have a different opinion on this. It is based on what I have suggested before.
The SAP note 1476239 - SAP system migration to Windows 2008/2008 R2 suggested this:
SAP systems based on SAP NetWeaver '04 SR1 (Web AS 6.40), 4.6 and 4.7 SAP systems:
As you have an SQL Server database then you should refer to the note
1476928 - System copy of SAP systems on Windows 2008 (R2): SQL Server
For SAP releases based on Web AS 6.40 SR1 and lower, you must start the upgrade immediately after the system migration. During the upgrade you must not use the system productively until you reach the end of the upgrade downtime. During the upgrade of these SAP releases, errors might occur in the DB-specific monitoring tools such as transactions DB02, ST04, DB12 and DB13 etc. These releases are not supported on SQL Server 2008 or higher, and you can ignore such errors during the upgrade.
It means you will copy (Homogeneous) the existing system to a new hardware and start the upgrade without doing an SP update before starting the upgrade.
Finally, do a sandbox upgrade and see how the upgrade goes or check with SAP and get this clarified.
Cheers
Reagan