I received the same email today. It doesn't look like a true BOGO as they reference "special companion pricing" if you buy anywhere from 2 to 6 seats. Given the F cabin has 8 seats, I'm skeptical the discount is significant. Further, when I click on the booking link with the promo code, it appears you can only depart from US gateways on LH metal and each departure city has very specific and limited destinations which vary by gateway. Further, when searching for availability within the confines of the routing and dates they provide, I have found absolutely NO availability for they 6 or so scenarios I attempted.
https://www.lufthansa.com/us/en/firs...e15af6&mi_sc=t