Prior to 1983 (VIN 7355) the steering rack was fitted with a circlip in the top of the pinion housing and rectangular mounting feet.
From VIN 07356 the top of the pinion housing was peened over. If you are ordering a seal kit please check which type of pinion you have.
The rack itself is interchangeable.
From 1988 (VIN 24496 approx) the front subframe changed and this meant that the mounting points for the steering rack brackets were repositioned. The steering racks were modified and had oval mounting feet. These later types of rack were then supplied as a replacement for the earlier racks with rectangular shaped mounting feet (albeit with a modified lower steering column and extra mounting brackets).
Before ordering a replacement steering rack please ensure what shaped mounting feet your rack has.