Hmm, I didn't get that from the book. In fact, there's a part when John is recounting a memory where they drop Billy off at his parents' place, the band joins them for a turkey dinner, and Billy plays this acoustic guitar for his nieces and nephews. It's John's version of how Billy got the scar on his hand -- the guitar blows up because it's "unacclimatized to our weather"... I suppose one could make a case for the scene being a metaphor, but I think it would be reaching a bit far.

There is a part when Pipe reveals that Joe comes from money, John & Billy are middle class (comfortable enough to have bought equipment), but that Pipe basically had to stick with the original drum kit his parents bought.