Well, the pre-made sabers you find later, throughout the game are randomly generated.
It's possible to save the game and fight X monster or open X box or initiate X conversation, etc., which rewards you with a saber, and have a different result than the previous time you tried.
Same with the color of the sabers you find, iirc.
Thus, if you really want a short saber for the offhand, and you just found a double-saber instead, and you have a recent Savegame, it might be worth it to restart at the save point and see if you get a short one the next time.