It seems it can represent any time period from the Qin or early Han to the end of the 3 Kingdoms but the representational details is about right. Use of chariots for command vehicles is still present in the Han and maybe in 3 Kingdoms but later discarded in later periods. At the same time, you have standing cavalry, which although introduced in the late Warring States period, has its greatest impact and institutionalization under the Han. One cannot see the details on the polearms, but the Han period still saw considerable use of the Ji or Ge or dagger axe, but later Chinese armies abandoned that and solely use the spear.