Transmission Numbers

The 73 is the year and the number of boxes marked indicates the month. I don't know what the 3410432-2 is. Is it stamped above the boxes? Part number perhaps. There should be a number stamped just above the pan rail on the drivers side. This number will indicate the original application of the trans. Here is a link:
http://www.mymopar.com/downloads/transguide.pdf
Use the first 7 digits of the number. The trans came in the natural cast aluminum, they were not painted.