Hi Robert,  I have a Gulbransen Country Seat Model player. Your piano
number 293315 is listed in the Pierce Piano Atlas as having been made in
1928 that year beginning with 282000 and 1929 starting with 300000.

The auto sustain switch for my piano is on the left side wall of the roll
mechanism. It has a curved metal plate that says sustain. The lever moved
forward turns it off. Pushing the lever forward turns on the automatic
function.

As for registering I believe that this refers to the fact that the
tracker bar can be adjusted by the tracking knob several notes in either
direction to change the key in which the roll is played.  My piano is a
straight 88 note player not a reproducing piano.

Jack M. Conway, Los Angeles, California, USA