Will factory rims and tires from a 2001 Pontiac grand am fit on 2003 am?

Yes, the factory rims and tires from a 2001 Pontiac Grand Am should fit on a 2003 Pontiac Grand Am. Both models have very similar wheel specifications. However, always double-check the tire size to ensure it's within the acceptable range for the 2003 model's specifications (found in the owner's manual or on a sticker inside the driver's side doorjamb). While bolt patterns are likely the same, slight variations in offset might exist, but it's unlikely to be a significant problem for a direct swap between these two model years.