I'm scratching my head on this one. I'm from Maryland and totally understand the mold thing, but in all my experiences, the box goes first before the disks get done in.
What condition are the boxes in?
The only thing I can think of is that he had all the disks in a disk case or something and that is how they all get infected and not the boxes. But the outside of the disks would have the film also...
Perplexing.
As for the mold itself, I'd get it tested. No joke, I lived in my parents basement for years, moved out in '98, went back to visit last year and ALL the dry wall was pulled down for black mold. Apparently the stuff is toxic or something and fairly invisible unless in large colonies.
I know I'm sounding like a real conspiracy theorist right now, but I'm really just lookin' out for ya. GOOD LUCK!