Need help finding new 7.25 7 1/4 spider gears for 9 bolt cover rear

HI , 1972 DART in the shop and open and needs rebuild . the shop needs the spider gears for the 9 bolt style 7.25 ( 7 1/4 ) rear. they said they tried randys but i will check again . but other than randy ring and pinion , can anybody help me find the gears ?? OR is there a difference between the spider gears for 10 bolt and 9 bolt ?? please help asap , thanks ! -jon