I get the impression Steve played around with the momma/prison verse a lot, and may never have sung it the same way twice. He sure was having a good time on the recording I transcribed from.
Yeah, I had trouble believing Prine would refuse credit for the song because it was "goofy" - he may have said that, but it may be he just thought his friend Steve should get all the credit. Prine's "too goofy" statement was cited in the notes on the No Big Surprise anthology; but on the recording, Goodman says Prine wrote it with him.
-Joe Offer-