yes, the reason 5 windows seem more common nowadays is that's what has survived, what all the hobbyists want, and what's most common at show[off] meets .... also likely the majority of the [cheaper] 3 windows were worked to death long ago, as working mens trucks were meant to be .... if someone could come up with factory numbers on how many of each were produced I'd bet donuts that 3 windows accounted for over 75% of production and now account for 95% of the AD's found behind barns everywhere - same with big window TF trucks, fewer made, more preserved
Bill