Just want to let you all know, the head is back on, this time with the tool.
But one thing remains you can insert the 123 ignition the wrong way.
In the correct position it just drops in the wrong position it goes in a bit tighter but without the need of any force.
I dug up my old distributor and tried the same, but there is no way you can insert this one the wrong way.
I think the problem is the slightly different shaft design and the very flexible coupling on the 123.