No, it's like saying that if you release under Apache license, it's not open source even though it's under an open source license
For something to be open source it needs to have sources released. Sources are the things in the preferred format to be edited. So the code used for training is obviously source (people can edit the training code to change something about the released weights). Also the training data, under the same rationale: people can select which data is used for training to change the weights
Well, this is just semantics. I can have a repo that includes a collection of json files that I had generated via a semi-manual build process that depends on everything from the state of my microbiome to my cat's scratching pattern during Mercury's last retrograde. If I attach an open source license to it, then that's the source - do with it what you will. Otherwise, I don't see how this discussion doesn't lead to "you must first invent the universe".