Not sure what SN this is for, but probably SN20 for the first orbital attempt. It's a new arrangement of heat shield tiles.
These were the 2 sections with visible labels in the production yard near the high bay:
The technical details of the Heat Exchanger Methane Sub-Coolers:
An entire rainbow over SpaceX’s Starbase launch site. 🌈🚀🤩@NASASpaceflight
CATO (Crane Assisted Take Off) for the Launch Tower segment.Meanwhile, the SPMT has arrived at the suborbital launch site with a Starship stand, which likely means Starship SN15 will not fly again.➡️youtube.com/watch?v=zZjBO9…
The first tower segment lift is underway. #Starship
Tower segments almost aligned