390 With Double-Spring Valves?

I have a 64 galaxie with a T-Bird 390 4bbl. I need to find out if it has dual valve springs or not. I know it sounds crazy, but I opened the valve covers and can't be positive. It looks like a coiled plastic insert inside the valve spring and I can't tell if there is another spring beyond that.

Is there a way to find out by checking the engine stamp? Am I missing the obvious? Any help would be great. Thanks.

Your probably looking at the inner damper spring inside the valve spring. So yes you have dual springs. If your replacing them get the same type with the inner damper spring. Just be certain they are compatable with your cam specs......G.

G.