I was watching one my favorite old movies, "The Big Steal" from 1949 with Robert Mitchum, Jane Greer and William Bendix. In the film, the bad guy is driving a "41 Mercury club coupe but the interior shot shows the dashboard to definitely be a P15 and not a Mercury. Note how the word PLYMOUTH has been covered over on the emblem above the speaker grille. Regardless of this inaccuracy, the is a really cool old film with plenty of car action going on.
John R