It's more likely that the movie and the company chose the name because of its meaning. A convoy is literally a group of ships or vehicles transporting something, usually protected.
The Peckinpah movie (and the hit C.W. McCall song that inspired it several years earlier) stands among the most famous instances of trucking in popular culture-- I would guess rather strongly that it's a reference.
http://www.merriam-webster.com/dictionary/convoy