There is also the novelization of The Empire Strikes Back by Donald F. Glut , which came out in 1980 , several years before that Marvel comic was released . It described Boba Fett thusly , “He was dressed in a weapon-covered, armored spacesuit, the kind worn by a group of evil warriors defeated by the Jedi Knights during the Clone Wars.”
Back in the day , I took this as gospel ,and always imagined that the Mandalorians would be uniform in appearance ,rather than having so many different colors and variations ,as is the case today . When the Death Watch first appeared in The Clone Wars animated series ,that is largely how I imagined them . I think it’s also plausible that Lucas read that description in the novel , or perhaps more plausible that Filoni brought it to his attention during story meetings .