No, I believe they are Gunther and Ernst (based, obviously, on Siegfried and Roy).

Oddly, though, I was just thinking about the fact that in the way that I learned about The Barber of Seville, et al., from Warner Bros. cartoons, there might be some kids out there that learned about H.M.S. Pinafore from The Simpsons.

References:
http://www.snpp.com/episodes/5F04
http://www.snpp.com/episodes/1F08.html
http://www.davemackey.com/animation/wb/1950.html
http://www.snpp.com/episodes/9F22.html