Actually, it IS possible to have a Vulcan in an SEL. I have seen it, just as I have seen a Duratec column shifter. Ford can't make up their mind with that car...
But yes, the SEL is the top branded trim, while the SE is the base in all 2000+ 4th Gens (Unless you count the LX, which I believe was only for fleets?). I drove a 2001 SEL fully loaded and it was very nice. We have a 2000 SE Vulcan in the dark blue metallic, which is drop dead gorgeous in the sun. It has a slight tinge of purple in the reflection. Very neat color.
