Dear Karan,
At least not since Alain or I do the artwork. We've used Denmark from the start: http://wiki.centos.org/ArtWork/Fonts
Might be my bad memory acting up again, but did we actually discuss this change and decide to change the font ? If we did, why didn't we change it across the board everywhere ?
I have once suggested to change the font but did not come up with an alternative to stick with. Of course, If we change it, this needs to be implemented everywhere, But the distro itself is a good point to start. I personally would suggest to change it with 6.0 and not within a minor release or in 7.0.