He presumably did not have access to the court's opinion before it was released, but he did have access to internal White House legal opinions before the tariffs were announced ("Mr. President this is illegal and very likely to be overturned by the courts"), and he obviously had access to the entire federal legal team during the court cases.

I can't prove that there was any White House advisory memo before the tariffs were announced, but hypothetically, would this not be considered material nonpublic information? It seems the same as a corporate insider dumping stock because a company lawyer privately told them "we're definitely going to lose this case".