Welcome aboard!
The hood number was assigned to the truck from the day it was sent out of Toledo. It stays with the truck its entire life.
Without the bumper numbers there is really no way of knowing what unit the truck served with, or where it was sent to in its former life. It seems there really have been no records turned up anywhere to detail any service information about the M715's even if you did know its unit.
Be glad you had a hood number. My truck had nothing at all. At least nothing legible other than a few Kentucky National Guard markings on the rear bumperette under a couple layers of paint.
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