Its likely the one and same family.
Jacob who is listed frequently as James father but I believe is James grandfather given ages/DOB as below:
Jacob Holtzclaw
Born: 17 Feb 1738
Germantown, Fauquier, Virginia, USA
Died: 21 Oct 1812
Harrodsburg, Mercer, Kentucky, USA
Jacob's Father:
Hans Jacob Holtzclaw
Born: 1683
Truppbach, Nassau-Siegen, [state], Germany
Died: 1760
Germantown, Fauquier, Virginia, USA
Harrodsburg Ky is one of the oldest settlements in the sate and origianlly was in Lincoln County from which Mercer county was formed. Check this link for a good history of the time period involved.
http://www.merceronline.com/history.htm
John R.