ok, i've been installing my TES in my free time, and i'm almost done now.. i've been bolting on the passenger side (in a 91Z8 305 TPI) and on the farthest bolt hole, there is two holes, on one side of the head... i don't know if i'm making sense, so i'll try and get a pic up.
-Abe

 

Makes sense. Theres an extra bolt hole on each side, I guess that sounds right... the passenger rear and driver side front. Use whatever one you need to bolt up the headers. No worries.