I've seen Carryall Suburban as a model name.
GMC called their version of the Cameo pickup a Suburban and there was a Chrysler product that was called a Suburban back in the 50's.
If you go to
www.OldGMCtrucks.com (as I type this the site isn't responding) and look around you'll see GMC Suburbans clearly called Suburbans in factory literature.