No, it's not required. I have an external LG DVD writer that I've used with both my 2008 MBP and my aluminum MB.
Also an FYI, the term SuperDrive only refers to a Mac's optical drive, and the term external SuperDrive refers to the Apple branded external optical drive for the MacBook Air/Mac Mini. The generic term is "external DVD/Blu-ray drive" just to avoid further confusion.
Lastly, the external SuperDrive is designed to work with the MacBook Air and Mac Mini, and AFAIK does not work with other MacBooks or MacBook Pros.