The upper/inner bushes (Volvo #87033) are the ones that wear quickest and are the easiest to replace. They also give the biggest noticeable improvement, so a quick/easy way to sharpen up your front end. These are marked "B" on the IPD diagram. With care, these can be replaced one at a time on the car. Make sure all of the nuts are free and removable before starting. New nylocks a good idea anyway. The lower/inner bushes, marked "A", need to be pressed in so the arms need to come off the car. Removing the arm is almost certainly going to be difficult as the spindle that goes from one side to the other rusts in solid. Besides Kroil or Blaster you may need to resort to hammers, drifts and heat, along with a lot of words not found in Funk & Wagnall. This shaft is NLA as far as I know so attack it your own risk. The push rods for the anti-roll bar also rust into the spacer tube but that's usually fixable. New ones not too expensive. Bushes top and bottom marked "C". The 2 bushes for the anti roll bar (not shown) are clamped to the front cross member. If you haven't inspected these recently, check the cross member carefully for rust. It is a common trouble spot.
Work safely. Use secure jack stands, you'll need them to be VERY stable when attacking the lower spindle! Soaking everything in Kroil daily, for a couple of weeks, may save you a lot of grief. Good luck.