The first-generation Polo, a rebadged version of the Audi 50, was introduced in 1975 and was produced until October 1981. By 1979, 500,000 Polos were produced worldwide. It shared the internal designation Typ 86 with the Audi 50.
The differences between the Audi and Volkswagen models were minor, with the Polo being cheaper and much more basic. The two cars were initially sold alongside each other, but the Audi 50 never sold as well, and was withdrawn in 1978. The Polo was manufactured at the Volkswagen plant in Wolfsburg.
In 1977, the Derby saloon was released, which was simply a Polo, identical to the hatchback from the C-pillar forward, with a large boot attached (an Audi proposal which was never sold by them).
Facelift (1979–1981)
The Mark I Polo and Derby were facelifted in 1979. Sometimes referred to as the Mark IF, the facelifted model featured plastic bumpers, a different front grille and a revised dashboard. The round headlights of the Derby were replaced with square ones, bringing it into line with the similar (but larger) Golf-based Jetta saloon.
info from wikipedia