At 300k, the car needs it all if original.
Add coil springs to your list as they do sag with age. BTDT. Same with new shims. Caster rod/guide rod mounts fail pretty often on these as they take the load and debris from the road can puncture the boot, ball joints last a long while. The clover looking deal on the back of the guide rod bush will induce some noise before the bushing fails. You can always reboot a BJ if you catch it early enough, I have after a front end build. Remove that back cover and whack the caster rod on the ground and the old assembly will pop right out, seriously. Clean that scale in there until shiny. Toss them in the freezer and prep your hydraulic press, they go in easy with Astroglide or the like. Consider replacing the two bushings per bracket too.
LCA bushings are a nightmare to press in square. I suggest buying an additional kit just in case and/or finding a shop that can do them. I lack the skill or tools to press all three pieces in correctly. I bought the BJ tool and it has paid for itself many times over. Many people rig up all sorts of things for those, once you use the real tool for the BJs you will never try another way. A 5lb sledge and a 27mm? socket works perfect to pound the old ones out. Spray with Kroil or the like and let sit overnight.
I have done front ends on five W126 now, I am faster each time but certainly there are more tricks I have yet to discover. Just mark it all and pull it all out at once. A scribe is your pal here on the LCA eccentrics to get you in the ball park. Use a tape measure to make the caster rods as close as you can.
Agreed on brake rotors, if questionable... do them. Repack the bearings is a given. Mind their specific end play!
You will be amazed how tight and quiet a fresh front end is on these cars. Hope you can find a shop smart enough to align these, bad tires will induce pull. I think we add about 1* additional caster on passenger side due to road curvature.
Good luck!