I believe that Sparda, or the Legendary Dark Knight who is playable in DmC1 has the ability to turn the Yamato Sword, one of his (Sparda's) keepsakes into the Sparda Sword when he puts in enough Devil Trigger power through it during combat. Having that said bought me to another conclusion, what if the Legendary Dark Knight uses the Rebellion Sword and puts in Devil Trigger through it? would it also turn into a replica of the Sparda Sword? Possibly, since the Rebellion Sword is one of sparda's keepsake as well. The Legendary Dark Knight could also turn the Rebellion Sword into a replica of the Sparda Sword when enough Devil Trigger energy is surged through it during combat.
So in the end, there isn't two or even three Sparda Swords. There is only one true Sparda Sword and two DT'ed replicas of the Sparda Sword with one of the DT'ed replicas justified theorically.
"Alot," isn't a word, don't merge the words "a" and "lot" together.