We're having HardiePlank siding installed and the house is being wrapped with Tyvek over the open studs. I saw that the guys ran Tyvek up to the window edges, taping it with the Tyvek tape. The old FortiFiber flashing (circa 1973) fell away prior to them doing this. They did not add any new flashing around the window before the Tyvek. Do they need to? Thanks.