Help Decode this Frame Vin#

[72stepside4WD]

I am trying to determine the year of my frame. I found a partial vin # stamped on the top of my frame rail near the steering box, and it reads 32Z514012, see attached pic. I have been told multiple times (by 2WD owners) that there should only be 1 number in front of the single letter, and that number identifies the year of the frame and the single letter is the assembly plant. Is it possible that numbers on a 4x4 frame would decode differently than on a 2wd? If you can decode these numbers I sure would love to know what I am sittin on. Thank you!