This is probably premature, but it seems like Tesla made an adapter for HW4 (coolant connections wider apart) to match HW3 (centered, closer together):
All the cameras (5MP RGGB? vs 1.2MP RCCB) are in the same locations except a dummy replaces the narrow/far camera (covered by higher resolution main camera). Potentially this could all be retrofitable for vehicles compatible with HW3 including 2016 vehicles originally with HW2?
As many of us know here, Tesla has had plenty of experience replacing cameras and FSD computer, so they must be "excellent" in their process if they need to do it again with HW4…