Compare these two pictures. Sepia toning (faded brown) is on the left and Eurogeddon toning (yellow and saturated brown) is on the right.
You see the difference ? They are not the same. Sepia toning is more appropriate for the Great War but Eurogeddon toning is abstract enough to fit almost any decade of the 20th century
Sepia is more yellow, yours is over saturated sepia, but anywawy you are right you rstyle can fit what ever decade of the 20th century.