Is this Black mold, ghosting, or something else?

[Chris Miller]

Providing pictures below. Looking at bank owned property to rehab and live in for at least a few years. Roughly 3750 sqft built in 97. While everything looks relatively newer, we are noticing black patches, streaks, and circles the size of a fist. They are more spaced out and not tiny circle clusters like most pictures of black mold show. Looking at these pictures and description, could someone take a guess as to what this is? We hope it's just ghosting from the air, humidity, and or lack of insulation. However, it's a bank owned property and know they have been known to cover stuff up and sell as is with no disclosure so want to try to place it safe. Understand best bet is to get a professional opinion, but want to see what others best guess is from the pictures.