Really neat to see something clearly made after filming but before all the effects work was finalized (note the Tantive’s pre-hammerhead bow)
I haven’t actually been able to find out exactly when this comic strip was made. It looks more movie accurate than what Chaykin managed to do with the reference materia he was provided, but that could just be a matter of style. This version has its oddities as well, the Tantinve’s bow as you mentioned, and the Dewbacks looks more like regular lizards. But then again, they seem to be part of Williamson’s set of stock aliens. Tatooine also has several of Williamson’s trademark rock-formations.
It seems odd to me that Lucas wold have hired both Chaykin at Marvel, and Williamson for some newspaper, to do two separate adaptations at the same time. I can see how Marvel was talked into making the comic, but I don’t see how a newspaper would have commissioned a comic strip before SW had already become a hit. The Russ Manning comic strip started in 1979, so I would guess Williamson’s version would have been made somewhere between late 1977 and 1978.