When `package_version("pydantic-ai")` returns `None` (e.g., missing package metadata), the version check short-circuits and the code falls through to `register_hooks(hooks)`, which calls `request_context.model` — the exact attribute access the PR intends to gate behind `>= 1.73`. Consider treating a `None` version as if it is below the minimum safe version, or defaulting `are_request_hooks_available` to `False` in that case.