Is it possible that the school’s colors once were blue and gold? I can’t speak for high schools, but my elementary school has changed its colors since I attended, to the color of the high school to which it feeds. I have yet to learn why.
It’s entirely possible that you just happened to have gone to(what? 2-3 high schools?). And they just happened to have used this color scheme as the name of their newspaper/yearbook. It really, really was a popular color combination for all kinds of things as far back as the mid-1800s.
So, perhaps you just have some anecdotal evidence just as the others who have responded. It might mean nothing.