<VV> 64 oil seepage diagnosis and treatment?

[Ignacio Valdes]

My 64 has an oil seepage problem somewhere around the pan and/or valve
covers. Hard to tell where it is coming from. Pan or valve covers or both?
Not a lot, a few tablespoons each ride. All bolts are snug. The valve cover
gaskets are over 10 years old. Time to change? Should I change everything:
pan gasket, valve cover gaskets, drain plug washer? -- IV