Probus, RIC 291, NOT a dupondius, and not of Rome.

The "dupondius" which RIC cites from a Hirsch 1903 sale as from Rome, is a small module medallion of Ticinum.
Of the 3 "dupondii" RIC lists for Probus, 2 are small module medalions, and one a misdescribed aurelianus, also of Ticinum.

See: S. Estiot "Une campagne germanique de l'empereur Probus : l'atelier de Ticinum en 277-278"

Chronology: Estiot's 3rd emission of Ticinum, donativum, beginning of 278 CE.

RIC 291 = Hirsch VIII.2658; Gnecchi III p. 70, 75; "Rome". Bust type -, (-). Denomination: "Dupondius".

OBV.: IMP C PROBVS P F AVG Cesures: I_MP C PROBVS P F AVG

Radiate cuirassed bust left, with spear and shield; right hand holding horse's reins, horse's head behind.

REV.: VICTORIA AVG Cesures: VICTO_R_IA AVG

Trophy between two captives.

Mintmark: -|-//-

Weight: ?
Die axis: ?
Diameter: ?

Image provided courtesy of Universität Heidelberg