School me on 340 exhaust manifolds

Oct 10, what year? It was probably 69 for the 70 model year.

1970 Duster?

An Oct 10 Build date would be October of 1969.

. If my car is a 1970 duster and the fender tag build date is oct 10...wouldn't that mean it was built in oct 10 1970...as in the owner ordered it earlier?

I understand that if this car was pre made for 1970 it would have been built in late 1969...how can I tell the year my car was built?

I have all documentation for the car ( build sheet, fender tag, numbers matching)