It is the 1979 catalog. It is marked "T-79" in the corners. The catalog was put together in 1978. If you look at the black and red kettles they have small tabs on the lid. Especially the black kettles. The brown, blue and green ones are large tab lid vents. Heck Weber even recycled their old red "cut-away" kettle from earlier in the decade with small bowl tabs but slapped on some modern wheels to make it look current. We do know that there are examples of no date code w/ raised letters dark blue/dark green as well. No evidence of lime green with that vent.