Turret Alignments
I have aligned turrets many times.
On the Doosan machines there are dowel pins.
There are 4 tapered holes and only 2 pins used. The two unused holes are "Master Pin" holes. So, in theory, you can re-align the turret by inserting two new pins in the Master Pin holes.
If you know you will crash the turret, I'd suggest that you remove the two pins that are in the machine. This will allow the turret to move when crashed. If they are not removed then something else "Will" move. Allowing the turret to move during a crash makes the crash less severe. Now you can take the two pins you removed, loosen the turret bolts for the curvic coupling and align the turret with any of the 4 tapered holes. This works; I've done it many times.
On turrets that the pins were left in and the machine is crashed; the pins bend and often the saddle moves; making the alignment much more difficult.
Also, buy a co-ax indicator. It is the only way to be sure you get back to X0, Y0.
Find it, fix it, and leave it alone. But make sure you find it, make sure you fix it, before you leave it alone.