Rob, there should be essentially no play in an up-to-par MB steering system. A common spot on the 560SL is a steering "shock absorber" in the linkage, which gets worn and is an easy replacement. At 200K, the steering box itself may well need replacement if it's never been done, and there may be worn ball joints as well.
Yes, there are shock absorbers on the front wheels as well as the rear, and shock absorbers do wear out and need replacement. All other factors being equal, the fronts tend to wear faster in my experience since there's more weight forward.
Have your shop go over shocks, ball joints, bushings and the steering system. Of the above, only the steering box is in the major repair category (as determined by $$). Fix what they find and your suspension should be off the radar screen for a long time.
'97 SL500, 40th anniversary edition
'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)
SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)