I am considering the purchase of another Milano. It is a silver or gold edition with no sunroof. It has a 3.0 engine in it though

The current owner says that US models without the sunroof are almost 300lbs lighter than a USA 3.0 verde edition. I would like to know how much truth there is to this claim. I am planning to make this car a fast street/ autocrosser and it would ice the deal if I knew this to be lighter than the Verde I had been planning to strip. I could then sell the Verde unmolested

What differences cause weight variation in these cars?
Thanks
James