some one wants his truck to be rare.
The tool box was in fact a lower production number... 6% of 72 trucks (LWB 10 and 20...both c and k, pluss 20 and 30 longhorns) Only 2% of the tucks made in 72 were supers.
So the Super is more rare than the box.
Plugging numbers in... there were 394,973 long/fleets & Longhorns built in the model year 72. 6% of that is about 23,698.... a tad over 400.