If they're fingerprints, it's a very high coincidence for them to be sitting right over those pads. Instead it's possible that the reflow oven they used didn't put any solder there, and they used an iron at far too high of a temp to do so by hand. Or it's smudges, or it's something else, but those traces don't appear damaged so there'd be no point for the PCB to be burned there.
This is frankly, a decent analysis. Much more appropriate then "used board", which is quite frankly, ridiculous. I am all for remembering and recognizing everything Alpha-Technologies has done wrong and illegally, and let us not forget all their broken promises (contractual obligations..?..).. But please, let's be objective and not point out obvious bullshit about PCB discoloring like complete fools talking about things they do not know.
I stand by my own opinions regarding the boards having seen significant use. I've had hundreds of GPUs pass through my hands and PCB boards don't look like that when they are new. Believe what you like. Obviously it's only my opinion, just as you have yours.