Петр

Нашел решение.
Может быть, кому то будет интересно.

Spree::Order.class_eval do
  checkout_flow do
    go_to_state :address
    #go_to_state :payment, :if => lambda { |order| order.payment_required? }
    #go_to_state :confirm, :if => lambda { |order| order.confirmation_required? }
    go_to_state :complete
  end

  # If true, causes the payment step to happen during the checkout process
  def payment_required?
    return false
  end

  # If true, causes the confirmation step to happen during the checkout process
  def confirmation_required?
    return true
  end

end

Закинуть в:
/app/models/spree/order_decorator.rb