Chevy did not "engrave" anything on these cars. All tags/plates were either machine, or hand stamped.
The '70 model year was short, due to the long '69 production. GM basically made the (early)'71 production an "addition" to the '70 M.Y.(to a point) It is quite possible the trim tag is legit, as a "leftover" from '70. This would really depend on the date of production. I wouldn't expect to see this type of carry-over on a later production car, but a very early built car I think would be realistic. Can you get the production date, or even the VIN for the car? That would tell us.
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Joel Adams
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