Since the king has a beard and the archer is beardless, the archer is not the king. However, Alexander the great already used the bow and arrow as a royal symbol. In his symbology, the bow was either in a bow case or not.
Peter, it's been generally accepted that the reverse archer on Parthian drachms is the empire's founder Arsakes I, who we know was beardless from his portraits on his own coins. As Fred Shore states it in
Parthian Coins and History:Ten Dragons Against Rome, "The reverse (of drachms) showed an archer...This seated figure is Arsakes I, the founder of the dynasty, and deified hero of the Parthian nation. Ancestor worship was practiced among the Parthians, and was extended to their coinage."
In addition, it is likely that - as suggested by Vesta Sarkhosh Curtis of the British Museum and Sarah Stewart of the London Middle East Institute at SOAS - the archetype for the seated archer reverses predates Alexander. It may well have been an issue of Datames (sometimes referred to as Tarkumuwa), a satrap of Cappadocia from 385 – 362 BC, under the Achaemenid/Persian Empire. Around 375 BC he struck silver staters at the Tarsos, Cilicia mint that, on their reverses, depict him seated, wearing Persian dress (including the bashlyk and baggy trousers that the Parthians would later adopt), with empty sleeve (another motif borrowed by the Parthians), inspecting (or offering?) an arrow, with a bow to lower right and winged solar disk to upper right. As Curtis and Stewart state in an article entitled
The Iranian Revival in the Parthian Period: “This could indicate that the coins of the western satraps of the Achaemenid Empire (were) known to the early Arsacids once they took over power in Parthia.” Datames is shown in a 3/4 view whereas the Parthian archer is always in profile, and he (Datames) holds an arrow rather than the bow. But the similarities are clear enough.
Pics below courtesy of CNG and Parthia.com. Top row shows reverses of coins of Datames; the lower row illustrates reverses of two drachms of Arsakes I from the beginning of the Parthian Empire, and an Artabanos IV (216 - 224 AD) reverse from the final years of the Empire, showing the degenerated image of the archer:
