Hi. We have a panda with factory fitted Roof Bars. Please be careful when buying a rack to go on them. We thought we had the right ones but we had a very bad experience last summer when the whole assembly including the bikes came away from the factory fitted roof bars All we could do was watch the whole assembly lift of into the air and land behind us in the middle of a dual carriage way. Fortunately no one was hurt except the bikes of course.
We can't help you with the part numbers you require but if you go to Halfords they have a chart that they use to look up the correct Thule part numbers for the new Fiat Panda .They will be only to pleased to help you. You will notice when you have the right ones that they actully wrap right around the roof bars and lock with a key.
We went to Halfords and have now got the correct Thule racks and have had no problems since. Good Luck and Happy Cycling.