Nope..not screwed at all. Your options are:
The fasest--air hammer with cold chisel. Oh...weare safety goggles. I hate safety ***** and I even wear them when cutting metal, regardless of the method.
fire:--cut the heads of the rivets off with oxy aceteline or oxy propane torch then use a drift punch to punch them out the other side. If you use this method, watch out for gas lines, brake lines, wires, etc.
drill: You can drill out the heads with a small drill and step up the sizes after the drill goes past the button. Step up in 1/8" increments. Once you get to the diameter of the rivet drilled, use a cold chisel and knock the heads off then punch them through with drift.
brute force: BFH and 1/2" cold chisel and get on it. Try to get a rivet chisel (COLD CHISEL--NOT A HOT CHISEL OR WOOD CHISEL, SCREWDRIVER OR ANYTHING YOU DON'T KNOW CAN CUT COLD METAL-- Okay, maybe I am a safety ****). A rivet chisel will be flat on the bottom and wide. A regular cold chisel will work too, but if you use one, make a starter notch or a cut on the rivet with a dremel, file, hacksaw, etc.