Yes. Tom Joad is the protagonist of the novel, the son of an impoverished farm family kicked off their land. I don't know if Springsteen has talked about it, but he doesn't need to--it would be obvious to American children who read the book in school.

Tom Joad is a symbol of many of Springsteen's underappreciated working-class heroes, like the Vietnam vet in "Born in the U.S.A." (though Tom Joad is poorer than many working-class Americans because his times were more dire). You could do a great story on the parallels you find with Tom and Springsteen heroes whose "grapes of wrath are stored." (Although "grapes of wrath" is from the Bible, I suspect most Americans know the phrase better from "The Battle Hymn of the Republic.")