In one of the pictures you can see the MVP model badge next to the curb side headlight.
The single square headlight was also indicative of the MVP model. The Westcoaster/HDX had quad rectangle headlights.
And yes, all through the years the MVP model was offered Thomas still offered the Westcoaster/HDX. And due to the big price difference most districts opted for the MVP. As time went on people kept adding back in many heavier duty spe'c items from the Westcoaster/HDX. Finally Thomas dropped the MVP and now you can get an Transit Liner EF or Transit Liner ER with whatever spe'c's you want and there isn't much difference in the basic spe'c now. It is all a part of reducing choices in order to make assembly easier.
The same basic thing happened at Blue Bird with the TC1000/2000 and All American.