Gilly, my copy of Olson (The SL Experience) gives the "campaign" as covering 107's from 1972 to early 1985, but then identifies specifically 107.023-24 and 107.043-44 chassis. Olson's dates would include the 380 cars but his chassis numbers don't, and he does specifically state it's the 350/450 SL's and SLC's. Barrett (Illustrated Buyer's Guide) also states specifically that the 380's weren't affected, but both include the earlier cars back to the beginning of 107 production.
Olson does have a clear description, for anyone who wants to look under the car: The mount for the rear of the control arm is about 2 inches wide on the affected subframes. The later one is about 4 inches wide, with a reinforcement that connects the control arm mount to the subframe.
'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)