: I saw two different type of dials on Heuer
: Pasadena PVD with 7750.

: - One has white background chrono counters

: - The other (like mine, ref. 750.501) is
: monochronmatic with white counters in
: foreground (back color is the black of the
: dial)

I'm not sure I understand your description... But it wouldn't surprise me if Heuer used two (or more) different style dials. Somehow I suspect that Heuer didn't ordered too many dials too far in advance in case they wanted to switch production to different models in a hurry.

If you have pictures that illustrate your question (or can point to pictures on line), I'd love to see them.

-- Chuck