If a person dies and his last Will was not filed before his death, is that one valid or would the preceding one that was filed still be valid?

I do not practice in Pennsylvania.  In Florida, the later will supercedes the earlier one, especially if it says that it revokes prior wills.  If the later will does not say it revokes prior wills, the later provisions will apply if they conflict with the earlier ones.  Since the earlier will was filed, there may be an argument that the later will is fraudulent.  However, if the later will is clearly valid, it should supercede the earlier will.