Help To Figure If S&W Is RB or SB (TX)

[Tec_479]

Need some help to figure out if this S&W 19-4 is a RB or Sq. . On one side grip frame has a N other side has N in Circle and S . Here are a couple pictures of grip frame .

 

[wep45]

your pictures show a round butt revolver. the link below will show the difference between the round and square butt revolver.