Back years ago, when these cars were new. Discs were an option and when you ordered disc brakes they actually came with different (disc brake) wheels that would fit over the discs.
I can remember swapping wheels back in the early 70's and you had to be sure to get the disc brake versions if you had discs in front.
-=>Lee<=- Due to budget constraints the "light at the end of the tunnel" has been turned off!