drlucky-
How do you know it is original paint? If it's not it could be anything. Generally though, lacquer is much easier to rub out and is softer than enamel. If a fair amount of paint shows up on the buffer when you rub out the car and the paint tends to oxidize easily it probably is lacquer. If a small amount comes off and the car holds a shine it may be enamel. A good body shop may be able to help you determine the type of paint on the car.
LCJUTILA