In most cases, yes.
An employer is still lawfully required to pay your vacation pay even if you are terminated prior to using it. Under the Colorado Wage Act, if an employer provides paid vacation for an employee, the employer shall pay upon separation from employment all vacation pay earned and determinable in accordance with the terms of any agreement between the employer and the employee. This money is lawfully yours. If your employer is refusing to pay out your vacation pay upon separation you have a cause of action against them under the Colorado Wage Act.