I'm using ArcGIS 10.3
I have the following model taking a "xls" file and creates a "Shp" then passes KML format
as I do to export me the symbolism of the "shp" to "kml"
Here is the help for kml prepping. ArcGIS Help (10.2, 10.2.1, and 10.2.2)
Check the bit about layer symbology and whats allowed for each geometry type
Also, I believe you are looking for symbology there, not symbolism(an inversion of the classic Willem Dafoe correction)