Good score! I have had my set (green case and all) since 1967. Only a few of the taps have been replaced, and none of the dies. They are great tools.
These old sets are carbon steel, and should be used only by hand and with good cutting oil. They will last a long time if cared for.
My plastic case still works, but has suffered a couple of hits. My dad placed a pair of vice grips on top of the lid after he had heated something with a propane torch, so it has that imprint melted in. A friend borrowed the set and placed a lacquer-thinner soaked rag on the lid, melting and warping it in a different spot. But the lid still closes and latches!