In the breeding process, I am absolutely sure that during the breeding process they propagated using immature embryos. "Cloning" by definition implies vegetative propagation, and I'm sure when they finished the breeding process that is how they have propagated this cultivar.

If you are interested in more of the details, there is a wikipedia article on cotton candy grapes, If you look in the references, there are several articles with more on how the variety was produced.