You are correct, #19 is the shift lever and #24 is the shift rod lever.
There is a grease fitting in the end of the shift lever which seldom gets any grease allowing corrosion to build up inside. This causes the shifter to be stiff. The shift lever itself is brittle and will break easy if forced or if the motor is laid down on the shifter side. Applying lots of heat will help to remove the broken shifter.
Broken shifters on the six horse motors are quite common and I wish I had a photo for every repair I’ve seen. Some are completely haywire while others have been thought out quite well. A while back, I took some broken shift levers, cut some aluminum, and welded them up to more closely resemble the original. Not exactly correct but they all work.
