I've got labels from crack outs sitting next to my computer right here.. The coins have since been sent back in to be re-graded and graded the exact same. But I decided to save the old labels anyway. I usually let them know if something was a crack out so they can take the old serial number out of the system and not affect the population. It's not uncommon to have an old label. There'd be a lot of trust involved to claim something was associated with a label unless there were actual photos to compare to on the grading companies website.
Yeah, I collect East Asian cast coinage and slabs are just a joke in this field. There is a company in China that slabs them, but they aren't reliable. All the major services won't slab cast coins.