Xiongnu rectangular belt plaque with facing riders 3rd-2nd C. BCE

"6.1 The Origin of the Xiongnu and Their Customs: The ancestor of Xiongnu was a descendant of the ruler of the Xia dynasty called Chunwei*. At the time of Tang and Yu, there were nomadic tribes called Mountain Rong (Shan-Rong), Xianyun and Hunzhu. These peoples settled in the northern wilderness; they migrated from place to place with their livestock in search of pastures and water. The animals they raised were mostly horses, cattle, and sheep. However, they also raised rare animals including camels, donkeys, mules, hinnies jueti, fine steeds called taotu and scaled-markings fine horse called tuoxi**. They moved and migrated with their animals and did not have the practice of building walled-cities or settle down to conduct farming activities; their land tenure was patrimonial, each family or clan had its designated portion of land for grazing. They did not have writing, and all agreements were conducted verbally. The young boys learned to ride on sheep at an early age and were taught to shoot at birds and rats with bows and arrows; when they grew a little older, they hunt foxes and hares, which they used for food. Every man could draw a bow and was an armored mounted horseman. In times of peace, they herded their flocks and made a living by hunting, but in times of crisis they took up arms and went off on plundering and looting expeditions. It was their innate nature. They used bows and arrows as their long-range weapons; as for close-in combats, they employed swords and metal spears. 

Author's notes: *Xiahou was the first dynastic Kingdom of ancient China (2070-1600 BCE); later abbreviated as Xia.

Author's notes: ** Jueti is an animals crossed between a horse and a hinny - equus hinny. Taotu, taoxi. N.B. The Xiongnu probably raised and used the Przewalski's horse - Equus ferus Przewalski. The animal was identified by the Russian scientist Poliakov in 1881. It had 66 chromosomes, versus the domestic horse with 64. It was a hardy and robust animal much shorter than the domestic horse at 13 hands, or 1.32m at its shoulder and weighted around 300 Kg. The horse is now considered extinct in the wild."

-Hanshu Xiongnu Zhuan Volume 94 Number 64 A. The Western Regions, Xiongnu, and Han (from the Shiji, Hanshu, and Hou Hanshu) translated and annotated by Joseph P. Yap (page 275)  

Xiongnu rectangular belt plaque with facing riders 3rd-2nd C. BCE. Bronze. Hing Chao Collection. City University of Hong Kong.

A lot of the details are hard to make out, but it appears the two men both have large bushy mustaches. I traced the faces to show.

Source:

https://www.cityu.edu.hk/bg/exhibitions/hunters-warriors-spirits/early-nomads-china

Quote:

Hanshu Xiongnu Zhuan Volume 94 Number 64 A. The Western Regions, Xiongnu, and Han (from the Shiji, Hanshu, and Hou Hanshu) translated and annotated by Joseph P. Yap (page 275)