What wood should there be in the seat back of a 1924 touring?
I don't think tourings had any wood supports behind the back of the front seat. The seat back springs hung from cloth straps tacked to the upper front seat back sill wood.
There may have been a piece of cardboard between the seat back springs and sheet metal to reduce the squeaking (for a while).
here ya go.
Be sure to place a piece of felt in there, or it will vibrate.
The best thing to do is install some Dynamat type of insulation in there before you put the wood in, it makes the body more solid and less "tinny" sounding
I put the cardboard that the springs came in behind the seat of my 24 touring