I am not saying that your method for removing the cluster is wrong at all and I am not even really disagreeing with you....but...you have to realize that the "tool method" is the method prescribed by MB....or else they wouldn't make actually tools for it, and if I do remember correctly, that is what is in my service manual.
Also, I don't know how the tool method could break or scratch the cluster. I did it that way and had no problems. I am almost certain that the speedo on mine is electronic, making his 86 124 likely electronic too so a speedo cable does not come into play.
Again, it doesn't really matter...six of one and a half dozen of the other.....but I would hate to have to remove that lower panel just to pop out the cluster! Just seems more of a PITA than it has to be....that's all.