not sure about the 42 but the id number on 37s is also stamped on passenger frame rail just over the front axle/ leaf spring .i had to wire brush my frame to be able to read the numbers there. the PO IN my case used a id number off the motor and not the real id number for some reason.
if anyone has a copy of a 1937 Branhams automoblie referance book
you may find a better explaination there it will tell you how many were made cost what models there were etc. hope that helps Earl
