CAM shafts and CAM position sensors

I have a 2011 Kia sorento lx 3.5, and I took it to a shop and was told that the cam position sensors are bad and need to be changed, So I agreed to the shop fixing that issue. I receive a phone call a few days later from the shop telling me that I also have to change the cam shafts even though they are in working condition. They told me that they have to change the cam shafts because kia only makes updated cam position sensors and they don't fit the original camshafts, to me that's odd being that the car is only three years old can you explain to me if that is true?