The 450$ upgrade C-F was in the last days of Swissair in 2002. It is definitely gone. Currently they sometimes offer a Y-C upgrade on LH/LX for 600$ if they have free seats in C and overbooking in Y.
C-F necessitates paying the full fare difference Full Fare C- Full Fare F, which is about 5000$ afaik.

Flashing the silly dark Amex card will definitely reduce your chances to Zero, same btw in most hotels in Europe
Free upgrade with no status has a slim chance anyway as CLT-MUC is a HON light but SEN heavy route ( BMW and suppliers shuttle frequently on this leg ).