For post-Marian legions, that structure is incorrect. A legion had 10 cohorts of legionaires, 9 of which had 6 centuries of 80 men each, with the elite 1st cohort having 5 centuries of 160 men each, giving a total of 5120 infantrymen. Each legion had a small unit of cavalry, primarily used as scouts and couriers, adding another 120 men.