Upgrading Question - Manual Edit or Overwrite?

[Andyman1]

I'm working on a design for a company who's currently on MS2.

 

If i were to manually edit the files it'd take quite some time for me to get up to RC2 (updating to RC1 first, then up to RC2). If they don't have any contributions is it possible that I could just overwrite the old with the new download?

 

Then what would I do with the SQL, what edits would I have to do to that if this would work?

 

 

Thanks in advance