RIC VIII calls the two dots above the standard control marks, while the central dot is ignored (so it must be assumed that it is part of the standard). However, I believe that all these dots are actually part of the standard, like a tassel. These dots coincide with points on the standard and reflect the shape of the standard, higher in the middle and lower on the ends.
Constantius II
A.D. 337- 347
14mm 1.7gm
CONSTAN-TIVS AVG, pearl-diademed head.
GLOR-IA EXERC-ITVS, Two soldiers helmeted, stg. facing one another, reversed spear in outer hands, inner hands on shields resting on the ground; between them one standard.
In ex. SMAN gamma
RIC VIII Antioch 54
I just saw this example, in which the dots are clearly not part of the standard. RIC VIII Antioch 52