I fitted a 123 earlier this year on my 280. Thanks to the previous comments on the forum, the only modification needed was to turn the clamp upside down. No bending other than perhaps opening the clamp a little. I did on the bench and happy it sat flush.
It seems to fit well, and being alloy I only “pinched” it tight with the clamp.
If the engine viabrates so will the dizzy, but the dizzy should not wobble independently.
I hope this helps, feel free to pm me if you would like to talk.
Peter