I believe the top one either is Gen 2 with serial or Gen 3 without serial and the bottom part is Gen 1. They change the finish on the plasma orbitals because of some problems on fading upon using it from time to time And plasma Gen 1 fades that is why they change it to a smoother finish. There are more metal head experts here that can chime in on the details.
The top one is definitely Gen 3. the bottom one is Gen one or two. list the serial number and It will tell you which one it is. Early Juliet and Gen 1 tio2 have the same bone colored finish.