This is implausible. The gag about having a story trail off into badly-written nonsense was used in that dialogue, but clearly doesn't refer to the book as a whole.
The last dialogue of GEB is an excellent example of something he's been doing for the whole book, aligning a dialogue with a Bach canon. The six speakers line up very well with the Ricercar a 6, including in details such as the midpoint where the conversation changes topic and drops down to only three speakers, and everyone rejoins on a new theme.
The topic of the dialogue is Hofstadter's philosophy of consciousness, the thing which he wishes more people understood (which I don't personally believe, btw), and which he wrote most of I Am A Strange Loop to emphasize. He wanted people to read and understand that part.
It also ends with a signature "strange loop" flourish, introducing the "Author" as a speaker, who begins a quotation, the content of which (as implied by the page layout and the label "Author:" at the start of the introduction) is the entire book.
The last dialogue of GEB is an excellent example of something he's been doing for the whole book, aligning a dialogue with a Bach canon. The six speakers line up very well with the Ricercar a 6, including in details such as the midpoint where the conversation changes topic and drops down to only three speakers, and everyone rejoins on a new theme.
The topic of the dialogue is Hofstadter's philosophy of consciousness, the thing which he wishes more people understood (which I don't personally believe, btw), and which he wrote most of I Am A Strange Loop to emphasize. He wanted people to read and understand that part.
It also ends with a signature "strange loop" flourish, introducing the "Author" as a speaker, who begins a quotation, the content of which (as implied by the page layout and the label "Author:" at the start of the introduction) is the entire book.
If that's not the true end of GEB, what is?