random stroke weight/thickness script

That should work as well if you enable the "Scale Strokes and Effects" option and disable the "Transform Objects" option at the bottom of the Transform Each dialog.

Select items.  You can change min and max in the first line.

var min = 1, max = 5;
var array = [];
function push(items) {
    for (var i = 0; i < items.length; i++) {
        if (items[i].typename == "PathItem") {
            array.push(items[i]);
        } else if (items[i].typename == "GroupItem") {
            push(items[i].pageItems);
        } else if (items[i].typename == "CompoundPathItem") {
            push(items[i].pathItems);
        }
    }
}
push(app.selection);
for (var i = 0; i < array.length; i++) {
    if (array[i].stroked)
    var x = Math.floor(Math.random() * (max - min + 1)) + min;
    array[i].strokeWidth = x;
}