in this situation its totally unnecessary, a restore will overwrite the database as you want it.

why start detaching production databases and then not using the log file when you don't have to? No proper database recovery phase can take place without the original log file. Rebuild log is a last resort command if you don't have a log file or a suitable backup, it should be followed by a dbcc checkdb to check no corruptions. This is a method of restoring a database from production to development that is asking for trouble and I would not recommend.