There are some things that are best left unknown. This is one of them.
The only inspection I did on the turbo was to pinch the shaft with my finger and thumb to wiggle feeling for looseness.
If there is no need to take yours apart, why bother?
One tip that I have for removing bolts is that if it is tight after being unseated, reverse direction and tighten then reverse again. Repeat until it feels lose and/or the bolt is out.
in a light hearted, non inflammatory tone,
look at post#192 in what did you do to your W123 today. I have that kind of curiosity. I haven't tried to rebuilt a turbo yet... so, if it is cold, and the snow is deep for a while, and I'm not out skiing, or snowshoeing/hiking/snow camping, flying an airplane, training for a triathlon, or anything else,,,, I am curious, I like to take things apart and see if I can put it back together without too many extra parts left over. if the car does 0-60 in 19.95 seconds instead of 20 seconds, accounting for a standard deviation of 2 seconds, I win, and it takes my mind off of medical billing and insurance paperwork. I am not an expert of auto mechanics. I have had the opportunity while in school with a starving student budget and millionaire ideas had some Mercedes, BMW's, Porsches, and of course Ducati's. which necessitated that I sourced parts from the bone yard, or other used part suppliers, and learn how to fix/keep them running on my own. now, I have alternate transportation, and do not have to rely on the W123 as my primary vehicle, and it is fun to teach my kids how to turn a wrench.