The ad agency probably pitched the ad, received approval, then found a van
that was close enough to work for 99.99999% of the folk who would ever see
it.

There are outliers in every population group who not only have the
knowledge to spot mistakes ("That was clearly William Shatner's stunt
double") they have enough time on their hands to talk about it. Such
people can be safely ignored.

The agency knowingly or unknowingly used an incorrect bus, but it was
close enough and the point was made. The real mistake here is in thinking
that advertising is meant to be truthful.

--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR