Restore email from Backblaze backup

During the upgrade from Sierra to High Sierra, my system crashed. Apple was unable to restore so they installed High Sierra after wiping the drive. All my files were backed up in multiple locations. However, mail was backed up only to Backblaze (in the cloud).

Backblaze has now provided an external drive containing 100 GB of mail in Backblaze Restore/SF.I7/Users/fisher/Library/Mail. There are three folders: two of which (V2, V4) contain mail.

On my internal drive, ~/Library/Mail contains a folder V5 (and PersistenceInfo.plist).

How do I restore from the external drive? If I copy V2 and V4 to the same level as V5, will mail use the contents of those folders?