No. 8 1/4 takes 3" U bolts, 7 1/4 takes 2 1/2" U bolts. I don't know of any place that repros 7 1/4 plates.
OP, if all you did was snap the shock studs off, just put new ones on your old shock plates. Mancini has 'em. Mancini Racing Lower Rear Shock Stud