Does the tablet say Sagittarius?
The image at the bottom below shows what remains of Rear line 3 - The image of symbols for AN.BAR7 (equivalent to AN.NE) from Front line 5 are above it for comparison. The red arrows point to the end of the Vertical wedge of the symbol AN. The tablet here could be referring to "Noon" as it does on front line 5, rather than Sagittarius.
Photo credit: Olaf M. Teßmer, Vorderasiatisches Museum
If the missing symbol was PA, wouldn't the vertical wedge be slightly further away from the start of NE/BIL/BAR7?
If the missing symbol was AN, this would explain the larger gap between AN an the symbol before it.