Hehe. Hardly. You'd be surprised how someone doing 3D graphics or special effects/compositing etc, could make use of 64gb of ram. Sure, it's an insane amount, but certainly useful in choice circumstances.
Or they may just not be advertising it since it would cost a lot, and not be useful with any current programs,or probably any future ones, before everything else becomes to outdated.
A lot of Macs can have higher ram modules then Apple advertise them with. This is mainly because they weren't available yet when these macs came out and isn't really/officially tested. And as we have seen with the Airport, you can't change the specs if a product is already out and a new piece comes out that it can use (if anyone understands what I'm trying to say...). So probably it can handle the 4GB modules fine.