Lower Control Arm Bushings

One of my 71 340 Duster control arm bushing sleeves doesn't seem to be steel. One sleeve came out while I was pressing my pin out which was nice. On the other one I tried doing the weld a washer on method but my MIG would not strike an arc. It will everywhere else on the arm. I did a magnet test and it will not stick to the sleeve. Are some not steel?