But aren't we talking about import controls, and the import of information itself? This has serious First Amendment ramifications.
Also, the 5th and 9th amendments. For the government to sustain a blanket prohibition on any U.S. citizen even possessing what amounts to a broad, economically significant technology will very likely require a new act of congress which specifically defines and limits what is banned, when, why and how. SCOTUS will almost certainly see it as a "major question" subject to 'strict scrutiny' which is a very high bar.
The truth is no one knows, which is why it is first amendment ramifications. Eventually it will be “decided”, but the arguments indicate any decision will be of political desire, not logic, either way. Both sides have a strong case.
Generally, instructions to create something are speech, weights could pretty clearly be seen as instructions to create a chatbot.
All I am saying is that it is complicated, they could go either way with it.