I'll try using the terminology I came to use while researching/rebuilding the front end of my 126.
The 126 does have front subframe mounts -they are also called front bearing brackets ( and bushings). They can be replaced without removing the front springs.
Replacing them changes and improves ride quality in an aging MB.
The track rod mounts can be replaced at the same time if they are defective.Like psfred says, since you are there, you might as well replace the track mounts at the same time. They effect tracking/braking - not ride quality.
The guide rods themselves cannot come off the lower control arms with the spring in place.The (front) bolt holding the rod is hidden under the lower spring mount, which in turn is held in place by three bolts.You can only get at these by removing the spring.
You need to do the same(springs) to remove the lower control arms -
need to do that in order to replace the LCA bushings.Those do effect ride quality(at least I found that to be the case) and were very tough for me to replace, until I found a press. You can just keep going with the front end until you do it all. I spent several months doing it. worth while in a big way.