Not all GEDCOM files are accurate.It depends on where the person who put together the file obtained the info.You need to search census, deeds, family Bible records, birth and death records, search cemeteries, etc. if you are serious about an accurate genealogy. Not all posted genealogies are accurate...some are based on hearsay and copied from other sources with errors. As to birthdates... You may find varying dates from early records.For example the ages listed in census records may differ slightly from family Bible records and tombstone dates, but that is not unusual for pre 1900 records.You will find more accuracy by the time birth and death certificates were common or required. I'm guessing you descend from James Knox Polk Whitlock and maybe wife Eliza Jane Scott.I have not researced your line beyond James K. P. Whitlock (born ca 1849 in Iowa?).