I have what I believe is a 'late' 33, or early 34, standard sedan, much of it is very original, and the dash & garnish moldings seem to be original & in very good shape.
To 'muddy-the-water' here.... my dash & garnish moldings are what I would call satin black. I wouldn't call them grey, or, if they are grey, a very dark grey....
Sorry, I know this does not help the discussion. And, it makes me wonder, how many variations did Henry make ????
As for the 'formula', I don't have it. But, if I have the color you want, I have a very good & helpful PPG dealer that has a 'scanner', and I suspect that I could get him to come up with some data for you. (It would take me some time - he's not close by, and I go to him infrequently. I expect to see him within the next couple months - can't paint in the winter...)