I have checked the sway bar bushings and I've also tightened the control arm bolts. I only visually inspected the rack & pinion mounting bolts and they did not appear to be showing signs of movement.
I pursued it further today and I think it's excess play in the rack & pinion. There's some noticable play in it when it's off the ground and on all fours there's plenty of play in the steering wheel along with a slight clunking.
I'll check the rack & pinion bolts with a wrench next.
How hard is it to change a rack & pinion unit on a 92 Regal?