Wood screws whether tapered or straight once they are "timed" have to go back into the same hole again. This pertains to butt plate screws and trigger guards that have two screws, and even some for-end screws on the inside iron.
You might get lucky if you don't put them back, but most times when you buy a used gun and they are not "timed" is because they were put in the wrong hole.
Once you try to "time" the wrong screw, now the correct one will be loose.
Most butt plate screws from vintage guns are straight.
