Determining if the current item is part of an Order Guide in ServiceNow Client Script

isOrderGuide.js

function onLoad() {
    var isOrderGuide = g_service_catalog.isOrderGuide();
    if(isOrderGuide) {
        g_form.addInfoMessage("We're part of an order guide!");
    } else {
        g_form.addInfoMessage("We are not a part of an order guide.");
    }
}