Actually Mazzle did not come with a Fonts folder, it used Clearfont2 to change the in-game fonts.
If you created a Fonts folder but did not place any fonts with the same names as the fonts WoW uses:
- ARIALN.ttf
- FRIZQT__.ttf
- MORPHEUS.ttf, and
- skurrri.ttf
then the normal in-game fonts will NOT be overridden. The only time the in-game fonts will be overridden is if WoW finds a font with the exact same name as I have listed above in the World of Warcraft\Fonts folder or if an in-game mod (such as Clearfont) overrides the font.