Yes, you are correct the D35 did use the stud on the radius arm to mount the shock. It was very common for them to break off even when not twisting them around like this. I would not waste the time trying to pull the axle forward for the reason listed above, but also when pulling it forward the coils will want to bind up and will make it a pita to try and pop it all back into place. You are time and money ahead to drill out the rivets. When you do it make sure you have MANY drill bits available. These rivets are hard and will eat many drill bits. A couple of the bolts are alot of fun to get to. On my 86 one was located behind the fuel filter housing which I had to unbolt from the frame and pull out some to get a wrench on the bolt.
As for the other person asking if they needed to replace the radius arm bracket. It could be broken or tweaked, but that usually takes hitting something hard with the front axle or dropping onto something. Typically they don't get damaged too often. Unless you see it as being twisted up or cracked I wouldn't replace it. But when you do it you are correct, drill out the rivets, drop the bracket out (make sure the truck is on jack stands) and put in your new bushing set, and then reassemble and put grade 8 bolts in place of the old rivets.
99 F250 PSD 4x4, 5" DIY exhaust, CCV mod, DIY intake, PMT1 with DP Tuner chip (stock/40/80/120), BTS VB, Suncoast Extreme Trans with SD43 converter, FASS fuel system.
Trail Rig: 95 Ranger on Kingpin D60/14 bolt/D&D Doubler.