Some day my website will get a version of my "garment construction genealogies" analysis that looks at the various basic strategies in how to make clothing. The construction here falls in the style I'd describe as "front-opening non-overlapping robe, no gussets, simple continuous collar/facing". Except for the addition of the collar/facing, it's about the most basic front-opening robe treatment you'll find, so it would not be surprising if it shows up independently in a wide variety of cultures. Some construction strategies do seem to be distributed based on a single-source-and-dispersion pattern (based on where and when they appears) while others seem to have been invented multiple times. This particular type shows up so early that it's hard to tell.