mrg , your serial number is exactly what I expected, based on other examples with that rack, I believe it's likely original.
A couple of theories I have are that stamping plants may have switched over to war production earlier and supplies ran out , so they used the pod rack , which would have been in house for Hawthorne models , to supply bikes that were advertised to have twin lights . The other possibilitie is that the pod rack was to be the top rack for 1942 .