No. The curve for the archaeomagnetic intensity is based on a broader dataset than would be significantly affected just by changing the assumed date for the Beth-Shean event, and in particular is strongly based on carbon dating for the relevant period in the 10th century BCE.
This research demonstrates how an archaeointensity curve constructed from a dense archaeomagnetic dataset in which the chronology rests on radiocarbon (for periods before the eighth century BCE) and firm historical ages (from the eighth century BCE and on) can be used as a powerful chronological tool.