Hmmmmm ... I can't remember it the Dyna I got slips onto a 1 3/4 inch pipe or if it's 1 /3/4 inch diameter.
I believe they rate them as to what they slip on to, but I could be wrong.
EDIT: just looked at the Craiglist ad, I'm haven't read that Fat-Boy pipes work. I'm 100% sure that the Dyna Wide Glide pipes work almost bolt on and I've heard the Sportster pipes work but you need some bracket work.