Absolutely not. I have a classic 12" (lol) -- 867mhz. It's the hottest of them all and idles at about 135 F. The left palmrest is always warm, but never too hot to touch. It could get uncomfortable based on your environment, and current temperature preference. That's unlikely, however, because not even MS Word or Pages can stress a system that far. Heavy multi tasking during heavy typing... maybee, But I still say it won't get uncomfortably hot. This is, once again, coming from the user of the hottest Al book EVER (damn, I;m down to 126 prosc temp rite now! that's a chilly temp!).
I wouldn't worrk about it.