When Australian comic artist Phil Belbin (1925-1993) was unsuccessful in seeking to have his proposed adventure strip The Earlybirds accepted into the Australian newspapers in 1969, what did he do? He kindly offered the artwork to his good mate, John Dixon (1929-2015), and allowed him to incorporate into a 1973-4 Air Hawk adventure, Early Birds. Just how different the story was, I'm not sure. (I'll see if Phil's son Graeme has any proofs from the era, and let you know.) From the indication here, there doesn't seem to be much variation in the script or even the artwork....
Later in life after John had given up Air Hawk (in 1986), it was Phil Belbin -- then a well-recognised and established artist -- who encouraged John to try colour illustrations. He once said to me (in relation to Phil), "I'm still not sure if I should thank him or beat him over the head. It's a tough medium."