For the first time ever I am possibly not 100% convinced by your observation/argument. It seems to me that possibly the Montreal was its own "modern" watch unlike the Carrera, which while modern was an extension of an already established line. Also, the essence of the Heuer shield to me has always seemed to be the balancing act played out between the "E"s. In the Montreal, the middle stroke of the "E"s actually seems to be a bit more balanced than the asymetrical presentation of the "E"s in the Carrera and most other Heuers I have seen. Also, I'm not quite sure by what you are alluding to when you talk about serifs; neither logo has serifs, correct? Are you referring to the rounded edges of the Montreal typography versus the Carrera?