Yes certain NOS tubes are very good and well worth the price. The Gold Lion's are very good current production tubes and are very reliable. If you were putting them in a premier 16 or 17 then I would say give them a try. But the PV-12 is designed to such a level that it isn't going get the most out of NOS tubes IMO. I have used NOS Tele's in both my Premier 17 and 16 II cj pre-amps and they are very nice tubes. The Gold Lions are a nice upgrade to the more pedestrian current production tubes while still being reasonably priced.
Chuck