Align position to center of picked object and rotate it to bounding box

Hey everyone,

I tried but failed to create a script that changes the plates of f.e. a Shelf to my new modeled plate.

The script should change the plates of the shelf and align new plates to it, but should look to the bounding box of the old plates, its not enough to rotate in local mode, because the plates of the old shelf are been detached, so the axis is not correct anymore.

it is not necessary to scale to old plates, the new plates just need the right rotation and center position of the old plates from the shelf.

thx
Dragan