The 1970 Kelloggs cards I've had for 40 years always stored flat in top loaders or in card savers are uncracked and as nice as the day I got them.
I find it increasingly difficult to get uncracked 1970s Kelloggs cards 'in the wild'. Even the few i find often end up with a cracked corner from shipping.
I haven't looked at this one in a while and I am afraid