Greg Hetson
A guitar shop in Ithaca had a Gibson SG "autographed by Greg", except Greg doesn't think he ever signed it.
Jay
Meaning of 3 in Jay's autographs:
Jay: "The 3 is for Dale Earnhardt, I've been doing it for about 8 years now, and I just can't stop. Seems like part of my signature, doesn't look right without it.
Note: Ralph Dale Earnhardt was an American race car driver. His son Dale Earnhardt, Jr. (also a race car driver) happens to be a Bad Religion fan, as revealed by Jay himself in the Ask Jay thread, here on The Bad Religion Page.