I have a 1967 coupe barracuda with a low serial number and shipped march 1966.

16richard said
vin code shows 280000 out of factory but not the number in relation to barracudas?

Your assigned VIN ends in 318220.

it shows a 2 for the Hamtramck, MI assembly plant.

It also shows a 7 for the 1967 model year.

For the 1967 model year, Hamtramck built A & B-bodies.

Each body type did not have its own separate VIN sequence, so your Barracuda has the 218220th VIN assigned at this plant for the '67 model year.

(the first assigned VIN started at 100001)

To complicate that even further, these cars were not built in VIN sequence & were all mixed up by body types on the assembly lines when made.