No. it's only certain years, I believe around 1976-77 or so. The dealer can do a VMI on the car and see if it is an outstanding recall or if it was already done. I am unsure if they are still standing behind it or not (the affected cars being over 25 yrs old).
The procedure is to clean off the subfram in the areas where the lower control arms mount and inspect for cracks in the mounting areas. If NO cracks are present, they will pay to have these reinforcement plates called "gussetts" welded in.
If there ARE cracks, they will pay for a new front subframe, which will already have the reinforcements. MB will NOT pay for control arms or bushings, obviously it would be in the owners best interest to have them replaced at the same time, especially if control arm bushings have never been replaced. There shouldn't be extra labor involved to replace the arms, and they're not prohibitively expensive.
The recall was issued about 1984 or so, the owners at that time should have received a recall notice.
I did one of these (subframe replacements) about 2 summers ago, the car was still under 25 years old at that time. AsI said, I am unsure if MB is still honoring these now. Maybe they are.
I have done 3 or 4 inspections on these. 3 needed the gussetts welded in 9no cracks), and the one with the cracked subframe was really bad, one of the mounting ears was broke right off.