You need to weigh all the evidence and the reliability of each. A record of an event that is not contemporary with the event, but made long afterward, is much less reliable than a contemporary record of an event. In the case of a record made at the time of a person's death, the information on the record regarding their date and place of death is very reliable, but information on the record regarding their date and place of birth is much less reliable, particularly in the case of older records. It seems that you have contemporaneous records establishing that the parents were living in Westmoreland County shortly before and after the person's date of birth. I would put Westmoreland County as place of birth, mark it uncertain, and discuss the evidence in the bio.