ClassicCar

Lee's right, the serial number tells the tale - although as Huddy pointed-out, the chrome piece is usually the easiest way to tell a '46 from a '47 (although not as reliable).

Even in those cases, there are 'exceptions'. The year listed on the registration many times does not fit the serial number 'year' either - due to the way a particular state or jurisdiction identified the 'year' of manufacture (which in some cases, boiled down to the date of the initial sale or initial registration).

Also, (IMO) over the years there are many reasons why a 'nose piece' or other exterior sheet metal, etc., would have been exchanged for the next or previous year - they both fit either year. It may well have been a minor fender bender (and the only piece they could find was from the earlier or later year), or maybe the owner didn't like that thick (or thin) ring around the nose piece - i.e., any reason to change it out (?)... Who knows - maybe Hudson might have made a few '47s with the '46 nose piece on it?
In many cases, if there was an accident it all boiled down to what parts fit to make the vehicle presentable (and what was available or 'cheapest'). That goes for just about every year-range of hudsons/terraplanes/Essex, etc., where the sheetmetal and trim was equivalent or 'close', from year to year.

Some examples:
- I've got an NOS 38 112 fender, which can be made to 'fit' my '39 112 pickup, and will be putting '38 sedan doors on it as well;
- And, I have numerous parts from 40-47 which will work on my '46 pickups;

Keep us posted on the progress of your project Chris - We love to see pictures of 'works in progress'. Think of it as an online scrapbook, makes a great pictorial too.