No, Sarah is not a possessive noun. To make Sarah possessive, you must add an apostrophe s, making it Sarah's.
Forrest Seabury's birth name is Seabury, Sumner Forrest.
Forrest Sherman's birth name is Sherman, Forrest Percival.
Allan Forrest's birth name is Fisher, Allan Forrest.
Forrest Burns's birth name is Forrest G. Burns.
Forrest Tucker's birth name is Forrest Meredith Tucker.
Forrest Wilson's birth name is Robert Forrest Wilson.
Forrest Wood's birth name is Wood, Forrest Benjamin.
Forrest Pruett's birth name is Forrest Wayne Pruett.
Forrest Leisner's birth name is Forrest Tyler Leisner.
Forrest Halsey's birth name is Halsey, William Forrest.
Forrest Huff's birth name is William Forrest Huff.