although I doubt it's physically possible due to the reality distortion field, it would be hilarious if Steve hops up on stage and whips this out and says "and we decided that aluminum just didn't work, so we've went with a revolutionary glossy plastic back instead"
then everyone in the audience boos him off stage over fears of going back to the days of fearing touching your device lest you scratch it
IF it is plastic..he will "gloss" over the topic .....hee hee yes I said gloss
Probably say something like "the new design allows improved cell phone, wifi, and gps reception" The crowd won't boo..they will be all ooohs and aaaahs.