73 Gold Duster 198 slant 6
Nice Duster and extra special that it’s been in your family since new! As others have pointed out, what was installed on the line 50+ yrs ago might not be what was only available in the option/order sheets for the car line.
Quality control back then, when combined with financial contraints, also played a factor in what rolled out the door va what one could actually order.
Regardless your fender tag and window sticker/sheet confirm it came with that top. Keep the smile going and enjoy cruising around in the Duster!