Will a fender off an 2000 Crown Victoria fit 2003 car?

A fender from a 2000 Crown Victoria *might* fit a 2003 Crown Victoria, but it's not guaranteed. While they're the same generation, there could be subtle differences in bodywork between the model years. It's best to check part numbers to be absolutely sure. You should compare the part numbers from a parts catalog or online retailer for both years to verify compatibility. Even then, slight variations are possible.