Here are the scripts for REQ and sc_task

Request client script

function onLoad() {
	
	var callerLabel = $('label.sc_request.requested_for');
	var callerField = $('sys_display.sc_request.requested_for');
	if (!callerLabel || !callerField)
		return;
	
	/*if (!newValue) {
		callerLabel.setStyle({backgroundImage: ""});
			callerField.setStyle({color: ""});
				return;
			}*/
			
			g_form.getReference('requested_for', vipCallerCallbackREQ);
		}
		
		function vipCallerCallbackREQ(caller) {
			
			var callerLabel = $('label.sc_request.requested_for').down('label');
			var callerField = $('sys_display.sc_request.requested_for');
			if (!callerLabel || !callerField)
				return;
			
			//check for VIP status
			if (caller.vip == 'true') {
				var bgPosition = "95% 55%";
				if (document.documentElement.getAttribute('data-doctype') == 'true')
					bgPosition = "5% 45%";
				
				callerLabel.setStyle({backgroundImage: "url(images/icons/vip.gif)", backgroundRepeat: "no-repeat", backgroundPosition: bgPosition, paddingLeft: '30px' });
					//set callerField color
					callerField.setStyle({color: "red"});
					} else {
						callerLabel.setStyle({backgroundImage: ""});
							callerField.setStyle({color: ""});
							}
						}

Catalog task client script

function onLoad() {
	//Type appropriate comment here, and begin script below

	var callerLabel = $('label.sc_task.request_item.request.requested_for');
	var callerField = $('sys_display.sc_task.request_item.request.requested_for');
	if (!callerLabel || !callerField)
		return;


	var number = g_form.getValue('request_item');

	var ga = new GlideAjax("isVIP");
	ga.addParam("sysparm_name", "vip");
	ga.addParam("sysparm_numnber", number);
	ga.getXML(vipCallBack);

}


function vipCallBack(response) {

	var answer = response.responseXML.documentElement.getAttribute("answer");
	var callerLabel = $('label.sc_task.request_item.request.requested_for').down('label');
	var callerField = $('sys_display.sc_task.request_item.request.requested_for');
	if (!callerLabel || !callerField)
		return;


	//check for VIP status
	if (answer == 'true') {
		var bgPosition = "95% 55%";
		if (document.documentElement.getAttribute('data-doctype') == 'true')
			bgPosition = "5% 45%";

		callerLabel.setStyle({backgroundImage: "url(images/icons/vip.gif)", backgroundRepeat: "no-repeat", backgroundPosition: bgPosition, paddingLeft: '30px' });
		//set callerField color
		callerField.setStyle({color: "red"});
	} else {
		callerLabel.setStyle({backgroundImage: ""});
		callerField.setStyle({color: ""});
	}

}

We also need to make some changes to script include and sc_req_item client so that single script include fits for sc_task as well. Please update the below lines in earlier scripts

Script include update

gr.addQuery("sys_id", number);

Client script update

var number = g_form.getUniqueValue();