The GMC CCKW

I just bought a huge lot of parts from an old guy who got them surplus from the Air Force Base here years ago. A lot of NOS parts – I keep running across this part numbers on the boxes that start with G121. Anyone have any idea what vehicle G121 would be?

Thanks
Daniel

G121 would be Dodge 3/4 ton M6 carrige motor 37mm gun a link to site with many of the other g numbers
http://www.milweb.net/features/gnumbers.php

Great! thanks!