https://en.wikipedia.org/wiki/Export_of_cryptography_from_th...
AI is different though because these models are private, so they cannot really be considered to be "speech". Although if it were an open model it would likely be protected speech to release it.
In the case of the crypto export ban, the government was attempting to suppress the release of cryptographic research. For example, if a cryptographic researcher wrote a paper on a cipher and they included a definition of that cipher in the paper, that was an "export" of cryptography. This is very clearly a restraint on speech that violates the first amendment and after much legal wrangling the government agreed and the issue evaporated.