The difference between say that car being sold at numbers matching prices only to find out that it isn't is a lot of money.
AFAIK, the body tags correlated with the broadcast copy which correlates to the billing history....which then...PHS. I have never heard in 20 plus years any car that was a 400 or 326 HO that didn't have the correct code cowl tag.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.