ok i have a receipt here infront of me from A&L MOTORS in preston stating that they replaced both HG and resurfaced heads hmm now im sure doing this you would strip the heads to resurface them maybe im wrong but if im right then they should have fitted new valve stem seals :doh:
If i remember rightly the valves are recessed, so no need to remove them to skim head. It is good practice if the head is removed to do a leak check on valves at the very least. I personally would always remove and re-seat them and fit stem seals. Sadly not everyone works to the same standards.