Cover of Cosmo's Factory

On the cover of 1970's album Cosmos factory, Bassist Stu Cook is pictured front and center sitting down. At
his feet, there is a sighn that reads somthing like: LEAN, CLEAN, AND BLUESY. John fogerty is sitting on his motorcycle in the left side of the picture. on a post in front of him a Sighn reads: 3RD GENERATION. stu cook
is on his bike in the right side of the picture, and a sighn behind him reads: CREEDENCE CLEARWATER REVIVAL
BEWARE OF DO. is there anyone out ther who knows what these things mean? i would be grateful for any imput.