I got what might be a dumb question, but! Why is it that these trucks ( http://www.imcdb.org/vehicles_make-White_model-Western+Star+4900.html ) are not listed with these trucks ( http://www.imcdb.org/vehicles_make-White+Western+Star.html) ?

Because "Western Star" was put in model rather than in make with "White". I fixed it, thanks for the info.