I bought two bolts longer than the original, and it was only the longer of those two that protruded below the frame and allowed me to put a washer and Nylock nut on it.
BUT I can't say that there is any significant improvement in the "clunking," so I guess I have to think about replacing other parts as well. I couldn't feel any significant movement anywhere, but many of those other rubber bushings don't look too healthy.
Perce