This is from the 1973 Pontiac full-line brochure. Note the paint colors at the bottom. It seems that the bright yellow, second from the right, called "sunlight yellow", which looks like the yellow on this car, was not available on the full-size cars. The only color that looks like yellow that was available on the wagons is second from the left, and it doesn't look much like the yellow on this car.
Most likely a repainted. You can never account for one's taste in color. We've seen far worse on this forum.