Seca Turbo: 1982 or 1983?

I have a 1983 (supposedly) Turbo Seca. I say supposedly because the title says 1983, but I have it torn apart for winter maintenance and the VIN tag shows manufacture date of 5/82. I am hoping that in order for the bike to get here for the 1983 model year it would have needed to be in production prior to 83 ( I don't know, I am guessing). Is there a definitive way to tell? The 83's had the power-up kit and the fork tubes were 1mm thicker, but how do I tell?
Thanks
TR

 

http://www.xjbikes.com/forums/threads/tech-topic-model-id-and-vins.14577/

 

Measure the OD of the (chrome) fork tubes, 1982 models used 36mm fork tubes, 1983 models used 37mm tubes.

Or review the model ID aticle that k-moe posted.

A 5.82 build date could very well be a 1983 model.

 

Thank you both
The tenth digit of the VIN is D. Which makes it a 1983