AFAIK no gorilla glass (pyrex) on the MT4G
i had protector on my g1, but my N1 was naked (sept for the cute little condom for it that came in the box). never had any issues... the screen (well protective screen cover) on both is pretty robust... the MT4G even has dimpling on it to prevent glare (examine carefully in the sun if you dont believe me)
the smudges on this phone have been making me squirm though...
ROM: Iced Glacier
HTC Nexus 1:
T-mobile G1 Black x2 +1 white (warrantied out waaaay to many times)
*used for PSFreedom/XBMC remotes*