I beleave that I did hear it was a Limo but they were stretched further than they were originally for the movie.

http://www.imperialclub.com/Movies/Hudson/index.htm

http://www.customclassics.net/movie_willis.html

I am not sure that the cars in Hudson Hawk are original crowns..I think they were stretched for the movie regular 4 door sedans

Thanks

Imperial Crown Limousine,appear as bandits cars in the movie HUDSON HAWK starring by BRUCE WILLIS and DANNY AGNIELLO