Some were wondering why Model 3/Y deliveries continued even when S/X were still getting delayed, and seems like there was a separate not-Autopilot recall specific to S/X:
Beginning on December 9, 2023, software release 2023.38.200.2 was introduced in production, which incorporates the lockout functionality that complies with FMVSS No. 214, S9.2.3(b)(1).
That matches up with the version that people were able to take delivery.