It’s all right, ‘cuz they’re “Saved by the Bell”! At least, that’s what fans of the ’90s excessive-faculty sitcom will have believed concerning the squeaky-smooth solid of teens again in the day. How harmless we had been. How naïve. At the back of the scenes — faraway from the milkshakes and cheery cubicles of the Max — it seems the gang was once extra “West Facet Story” than Bayside High.