Some M-1 Carbine bayonets even made it to the top of Suribachi.
http://www.iwojima.com/raising/raisingb.htm
I have been following the M-1 Carbine discussion with interest and sharing it with a close friend and WWII arms collector, Richard Jacobson, a retired local police lieutenant. After consulting several collector's websites and other historical references, Rich assures me that there were indeed M-1 Carbine bayonets on Iwo.
This very topic has been an argument among collectors for years. The above photo was taken by Rosenthal moments after the iconic flag-raising photo was snapped. Note the carbine at the very left is an old style issue, while the carbine held high by the Marine 4th from the left has a bayonet fixed. Most of the remaining rifles in the photo can be identified as Garands. Bradley, Hayes, Sousley and Stank are among the happy faces. Most didn't get to go home.
Semper Fi,
B. F. Overton
CWO4 USMC (ret)