Are there any guarantees that harmful images weren’t used in these AI models?

Lol, highly doubt it. These AI assholes pretend that all the training data randomly fell into the model (off the back of a truck) and that they cannot possibly be held responsible for that or know anything about it because they were too busy innovating.

There's no guarantee that most regular porn sites don't contain csam or other exploitative imagery and video (sex trafficking victims). There's absolutely zero chance that there's any kind of guarantee.