Think of it like language, was there ever Latin speaking parents that gave birth to a French speaking child? No, it’s a gradual change. Or take a color gradient from blue to red there’s a definite change taking place but picking out one specific spot in the middle might be purple

1 ton refers to the cargo capacity in the bed, though that is more of an old naming convention as most of the 1 ton trucks can actually hold closer to 3 tons now.