Article with tables comparing Early Iron Age Phoenician-Palestinian inscriptions here.
The Gath inscription, reading ALWT | WLT or, possibly, ALYT | YLT (witness the Izbet Sartah ostracon’s Yodh) is an early alphabetic inscription inscribed in the Iron IIa. The ‘Izbet Sartah inscription provides a relatively close parallel to this inscription, and dates to either the Early Iron IIa (it was found in an Iron IIa context) or the Early Iron I (the script looked rather early, so it was dated to the earlier occupation phase). Apparently, the Gath, and, probably, Izbet Sartah inscriptions compared with the Zayit and Gezer inscriptions demonstrate two separate scribal traditions in 10th-9th C BC Western Palestine. The first, demonstrated by the Qeiyafa, Gath, and, probably, Izbet Sartah ostraca, is clearly not derived from the Phoenician cultural sphere from which came the Early Byblian inscriptions (note the G-shaped Lameds!). The second, demonstrated by Gezer and Zayit, clearly is. Perhaps, my guess the Gezer tablet is an Iron I inscription was wrong, and a non-Phoenician early alphabetic script was used in Iron Ages I and IIa, while the Phoenician script was only introduced c. 880 BC.