Color Labels

function changeColPref(num,r,g,b){
    var sect = "Label Preference Color Section 5";
    var key = "Label Color ID 2 # " + num.toString();
    var thePref = app.preferences.getPrefAsString(sect,key);
    //for reading
    function hexToRgb(str) {
        if ( /^#([0-9a-f]{3}|[0-9a-f]{6})$/ig.test(str) ) {
            var hex = str.substr(1);
            hex = hex.length == 3 ? hex.replace(/(.)/g, '$1$1') : hex;
            var rgb = parseInt(hex, 16);
            return 'rgb(' + [(rgb >> 16) & 255, (rgb >> 8) & 255, rgb
& 255].join(',') + ')';
        }
        }
    function ascii2hex(str) {
      var arr = [];
      for (var i = 0, l = str.length; i < l; i ++) {
        var hex = Number(str.charCodeAt(i)).toString(16);
        arr.push(hex);
      }
        return arr.join('');
        }
    //for writing
    function hex2Ascii(hex) {
        var str = '';
        for (var i = 0; i < hex.length; i += 2)
            str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
        return str;
        }
    function rgbToHex(r,g,b) {
        var out = '';
        //Adobe expects 4Chars, first one is always...
        for (var i = 0; i < 3; ++i) {
            var n = typeof arguments == 'number' ? arguments :
parseInt(arguments);
            if (isNaN(n) || n < 0 || n > 255) {
                return false;
            }
            //out+=" %" // so we decode  %22 %56 %99 - spaces between.
            out += (n < 16 ? '0' : '') + n.toString(16);
        }
        alert(out);
        return "FF"+out;  //#171717
        }
    var newCol = rgbToHex(r,g,b);
    var newColAscii = hex2Ascii(newCol);
    app.preferences.savePrefAsString(sect,key,newColAscii);
    app.preferences.saveToDisk();
    app.preferences.reload();
}//close change pref.
changeColPref(1,5,199,252);

This is the code that I used a few years ago, so have not looked at it since... perhaps you can muddle through it and see if it works with CC . . .