Looks like thay are different but ledgedary does have it...
Foam
68/69 CHRYSLER A & B-BODY MOLDED BUCKET SEAT FOAM | Legendary Auto Interiors
Upholstery
68 BARRACUDA DLX BUCKET SEAT UPHOLSTERY - BLACK | Legendary Auto Interiors
Ledgedarys website struggles, try googling it and it should come up. And note that they tend to put it on sale every weekend with better sales on holidays.
You could also look at Dante's
Dante’s | Mopar Parts Catalog |Classic Muscle Car Parts – Buy Mopar Parts and Classic Auto Accessories Online