Eh, maybe? We can’t reach into his mind. I really don’t see a motivation for them to lie in this particular context (literally no one would be mad if they said

Eh, maybe? We can’t reach into his mind. I really don’t see a motivation for them to lie in this particular context (literally no one would be mad if they said “we choose red markers because we thought Mars was probably red”). And I can understand being in a frantic state of mind to decode the first image of Mars as fast as possible, and the conscious consideration of the color set just not coming up. That sounds perfectly plausible to me. If that story is true, I’d also be pretty inclined to believe they were subconsciously influenced to pick a red color, even while hurrying. So, I don’t think it’s a total coincidence, but nothing about the story sounds particularly far fetched to me.