No, a few mm back and forth at most, looking at the distance between the stop and the little arm that shouldn’t normally hit it. You should check to see if the freewheel has seized in the alternator pulley. This common fault can cause the vibration. The pulley can be changed but you need a special tool that Laser Tools sells.
I would also replace the alternator pulley whilst you're at it if it hasn't been done as mine sheered off completely, and also replace the belt too for what it costs.
The only special tool needed is to remove this pulley from the alternator not the tensioner, unless you do what i did and remove the alternator and have it reconditioned and the new pulley fit at the same time as part of the job