Rivet Length Question

I was just about to attach the flaperon bracket reinforcements to the ribs when I noticed the rivets looked longer than needed. The callout is for ssb4-8s which, according to the good ol' web, has a grip range of .376"-.500". However, the actual dimension (not including a bit of Hysol) measures .334". Meanwhile, a ssb4-6s has a grip range of .313"-.375".

I realize that either one would probably hold just fine, especially with all that glue in there, but still...anybody have thoughts on this? How thick is the glue anyway??