Have a look in Section 5 General Information in your preview plans where it talks about riveting. You will find this note:
NOTE: There are times when the correct rivet length is not available. Depending on the application a shorter rivet can be used or a longer rivet cut to the proper length. Using a longer rivet, as is, can result in the shank being bent over like a nail. We have chosen to use a rivet that may seem too short in some places, but will do the job adequately.
I?m pretty sure this is one of those occasions where Van?s have chosen a shorter rivet that will do the job adequately.
Canberra, Australia (the nation's capital)
RV-7A #74351 Empennage finished (including the tips)
RV-8 VH-DAF (part-owned)
Working on wings and fuse
"A journey of a thousand miles begins with a single step."