do you know if they are held on just by screws to the body, or is there also double-sided adhesives? Am thinking about removing the fronts and leaving the backs. I guess I could check but thought someone bought them as aftermarket would know. TIA.

 

Both.

Actually the fronts are attached by two screws, a push pin and some double sided tape.

 

Personally, I'd leave them on. They seem to save the lower part of the doors from rocks and other stuff being kicked up by the tires.