<VV> Corvair body tag

[Borrrris at aol.com]

Hey all.  It was my research to interpret all the info on  my car's Fisher 
body tag that  led me to this group in the first place. Now  that I understand 
all the info the tag contains I'm left with a new  mystery.  Here goes:
 
My car is a '66 Monza coupe
My car's VIN indicates it is the 79,967 vehicle built at Willow Run  that 
year.
Its body tag shows it as body #28147, built first week of May (so I  figure 
it was about 3/4 of the way into that year's production)
Published figures show 103,743 corvairs built at ALL US plants that  year, of 
which 37,605 were Monza coupes.
 
So...what I can't figure is:
Since it's kinda unlikely that 51820 cars  (the  difference between the VIV 
and body tag number) built at Willow Run that year  didn't have bodies, I 
figure the body  number must indicate Monza coupes  only, right??
But supposedly only at Willow Run? If that's true, how to  explain that body 
#28147at Willow Run puts it at 3/4 of TOTAL  production for Monza coupes at 
ALL US plants that year, at about the  3/4 date in the production year (or that 
VIN 79967 is also about 3/4 of the  year's TOTAL production of 103,743 
Corvairs, not just at WRN?)
 
The kinda mystery I love to solve.  Who can  help?
Thanks, Matt M.