S. Bent Brothers Rocking Chair

This is a dark wood chair.  I am not good at recognizing wood type.

ON the bottom it has the S. Bent Brothers stamp.  You can see it in the picture.  There is also a serial number stamped into the bottom: 1273 883.  It is stamped in two rows.  The first four numbers in one row and the last three numbers in the second row.

There is a personal note on the bottom of the chair that is written in permenant marker.  The note is dated 8-1981.  I was wondering how much older the chair could be than this.

I don't believe it to be too much older.  I see modern phillips screws holding the legs into the bottom.

thanks