There’d be no reason to switch the angle of the saddle other than to make it intonate properly for a left-handed player.
The reason for the angle is to compensate for the gauges of the strings, the heavier bass strings need to be slightly longer than the thinner treble strings in order for the guitar to play in tune.
Because the current angle is wrong, the guitar will sound more out-of-tune the higher up the neck you play.
I’m not necessarily encouraging you to get it fixed. If it doesn’t bother you, or if you tend to play mainly in first position where the problem will be less noticeable, you may be able to live with it.
As for the former owner being a right-handed player, perhaps it was modified for a lefty before that person got it?