This particular coin is a good example, when everyone can honestly say: I don't see any trace of armor there. There are also such specimens from RIC VI area. But there are many more where some recognize a tiny detail as a trace of armor and others do not. Sutherland probably knew this, because he sometimes had good ideas in describing the busts.
For example, busts C and D for ROMA 71a - 89b (p. 358).
C - R., rad., dr., with or without cuir.
D- R., rad., dr., with or without cuir., seen from rear