I thought maybe the front spring perch and rear spring perch was the same but now looking at your photos it sure looks like the front perch has the spread angled wings on it and the rear perch with the shackle is more straight sided. Guaranteed to be a PITA no matter what to replace, even torching the rivits out,cleaning up the mount area of the frame and then resetting the new mounts with bolts is a whole weekend job with everything in front of you..for my money you'd be into new end-eye bolts as well for the springs. Might also be much easier to do one side at a time, meaning drop the u-bolts but that would mean replacing them as well. Any good spring shop can bend up new u-bolts for you. $15-20 bucks each and it all adds up around $500 in materials.
