Revealing mistake: In the fight scene right after the guards interrupt the duel, Porthos breaks his opponent's sword with a 3 bladed knife and then he throws a balled string which wraps around the guard's head. When the scene shifts to the guard's close up you can see the guard throw the wrap around ball himself. (00:28:55)
Revealing mistake: When D'Artagnan is in jail, right after he says "if you give me back my father's sword I'll cut your heart out", when Rochefort hits him in the back of the head you can see the sword handle never touches him. (00:33:15)
Revealing mistake: When Porthos shoots the assassin with a crossbow, he is a good distance below him. But when you see the assassin grab the bolt, it is straight in his body as if he'd been shot level.
Revealing mistake: It was obvious that Chris O'Donnell didn't sword train with his stunt double. His fighting style in the close up shots is completely different from his doubles style in far shots.
Answer: No. Inigo's sword has a jeweled hilt. D'Artagnan's is not jeweled.