No there are no external differences both the Preco (32000 series) and
Equipco (33000 series) fans are not seen from the outside. That being said,
some cars had a stencil or a flat metal plate where a fan pulley would be
located above the truck. According to Ed Hawkins this might have been to
alert employees that the cars had fans. On our website is a reprint of the
excellent article on these cars by Ed Hawkins from the MPHS Eagle. With
photos of the stencils and plates.
Kits will come, don't know when exactly.