Adding a little color here... There are already code points registered for pure ML-KEM on the basis of the draft.

The hybrid code point you reference is "preliminary" in the sense that when the RFC for hybrid ECC/ML-KEM is published (it's already been approved, https://datatracker.ietf.org/doc/draft-ietf-tls-ecdhe-mlkem/), it will replace the reference in the registry. However, it will have the same code point and the same semantics. If, for some reason, the IETF were to change the semantics, a new code point would have to be assigned for interop reasons.