Is there an out-of-universe reason for the Gundam series mech head designs? As I watch the shows I am constantly noticing the patterns in the head designs of the mobile suits.

Any true Gundam, or otherwise important mech, will always have two eyes and usually the V horns.
Any generic suit, or one belonging to a more shallow villain, will only have one eye.

Is this any kind of cultural reference?

EDIT

In Unicorn characters say that a mech becomes a Gundam when the horn opens into a V.  As if the V horns are something very specific.
According to Kunio Okawara, the mecha designer for the series:


  "I also put the form of the chonmage, which is a form of Japanese traditional haircut worn by men, and kabuto, which is a type of helmet first used by ancient Japanese warriors, into the design of Gundam. They are my inspirations that are concealed behind the creation of Gundam."