OK, update:
I went to the local Curtis compressor dealer and the guy didn't hesitate. He ID'd the compressor as a Campbell Hausfeld! I guess that makes sense since the tank is a Melben, who now makes tanks for CH.
Anyway, he gave me a source for parts here in Houston. I described the compressor to the lady and she said, yes they have that reed valve assembly. Come and get it.
Sure enough, they had one. It wasn't cheap though - $110! Plus $12 each for two gaskets. The guys at the shop said that pump was bulletproof though. They said they rebuild those and sell them with exchange for $650. A comparable new one from CH goes for $1200! So this is worth a couple hundred to freshen it up.
BTW Marv, they also have rings and bearings. So I'm going to clean it up, paint it CH blue, run it and see how it pumps up. If I hear any weird noises, I'll go back in and rework the bottom end.