What those who designed Trek imagined in 1964 may not be what those in charge imagined years later. Fiction is mutable like that - otherwise we'd have never gotten over all those incorrect James T
. Kirk references since WNMHGB. There is no one right answer - only what Matt Jefferies thought, what Gene Rodenberry thought, what Franz Joseph thought, what the ENT producers thought when they did their cute little retro episode etc.