thanks in advance
The object's .fillColor property has the details. Assuming you had a
reference to the frame then you need to get the .fillColor of the
reference. Samples are below...
var frameRef = app.selection[0] ;
var fillColorDetails = frameRef.fillColor ;
var fillColorName = frameRef.fillColor.name ;
var fillColorIsCMYK = (frameRef.fillColor.model ==
ColorModel.PROCESS) ;
var fillColorValueArray = frameRef.fillColor.colorValue ;