Starlog’s primary focus was sci-fi and fantasy, but they also did articles on science fact, especially about the space program. Just like the fiction news, some times that fact news didn’t come about as expected either.
In issue 6 (June 1977) there was an article about what we would see from NASA as a follow up to the successful Mars Viking mission, he is an excerpt:
The mission that NASA is now working on is the one that many space scientists would have preferred as the initial investigation. It calls for landing a pair of Mars Rovers ("Vikings on Wheels") on that planet's surface in the early 1980's. The Rovers would gather scientific data from several wide-ranging areas and send it to their mother Orbiter for relay to Earth. It is projected that these mission-controlled vehicles could travel up to three miles a day and help one another as needed.
NASA did have plans for a Mars rover mission in the late 70’s or early 80’s but they never made it off the drawing board. You can read more about them in these two articles from Wired:
This timeline turned out to be far to optimistic. After Viking the next successful Mars mission wouldn’t come until 1988 with the Russian Phobos 2 mission, a rover wouldn’t make it to Mars until the NASA Mars Pathfinder mission in 1996, and the plans for dual rovers on Mars would have to wait until the Mars Exploration Rover missions in 2003.