This dupondius is rare, but not unpublished.
A specimen in Copenhagen is described, but not illustrated, by Kaiser-Raiss, Die Münzprägung des Commodus, Frankfurt/M 1980, p. 122, 157+.
I have a specimen, from different dies than yours, acquired from a Davisson list, 1995. A little better preserved than yours, cost me $90.
A variant specimen with obverse bust radiate, draped right, from the same reverse die as your specimen, was in Sternberg XVIII, 1986, lot 516.