Corrected entry: The military used Hummers in the movie. H1 Hummers were not made until 1992.
Corrected entry: At the end of the movie, Bumblebee is seen talking to Optimus Prime and also showed fireballs falling to earth. In the 2007 Transformers movie, Optimus Prime and others didn't arrive on earth until the early 2000's.
Correction: This film serves as a soft reboot, ignoring many elements of the previous continuity.
Correction: The HMMWV (other wise known as Humvee) began production in 1983. Therefore there were military variations around in 1987. The civilian Hummer H1 was built in 1991.