yep they all have dots know, both the vivace and neo tat . .. ... .... to show cam size/stroke
the first neos had no marking showing stroke length on back and only takes the 1.8 & 2.5 cam then they went to these markings when they changed the frame & slide: ray confirmed this for me today.
c=1.8 cosmetic
x=2.5 extra
p=3.5 power