There are already some replacement seats for sale for our classics. But we know from experience that such new showpieces do not always fit as well when they are of a responsible sporty cut.
Then, for example, the chair cannot go far enough back or it forces itself on the door. That the handbrake and / or the belts are less accessible because of it.
It is therefore convenient to score seats at a location where there is stock. If one does not fit, then another can simply be chosen from the shelf.
With seats that are specifically made for your type of car, this phenomenon does not apply. Or less.