Edsel-Dan the difference in side marker lights is standard no thrills trucks got the square marker lights the deluxe or heavy option truck would get the stacked marker lights.
The various engine options that were available from a straight 6 to a big block V8 during the 67" thru 72" model year.
Did you know that this reissue kit is not a 72" it in fact a 67" or 68" ?
This pic shows the cab with the smaller back window available in 67" and first half of 68".