According to these studies, it does.

From the SEMA Research and Information Center -

According a study conducted by Western New England College's Department of Mechanical Engineers, "The best way to reduce drag, and improve gas mileage for pickup trucks, is to add a tonneau cover." Their study yielded gas mileage savings of 8% by adding a tonneau cover to a Dodge Ram.

From Auto Trim & Restyling News – August 2001

From "Tailgate Talk -Does Removing A Tailgate Effect Fuel Economy?"
By Bruce W. Smith

According to many experts, the best way to improve a pickup’s fuel economy is to leave the tailgate up and cover the bed with a quality aftermarket Tonneau cover.

"Tonneau covers on pickup boxes reduce aerodynamic drag,” said Ford’s Jack Williams. “We’ve seen reductions of about 8 to 10 percent on the F150. The average steady-state [cruise control] fuel economy improvement at highway speeds is closer to 5 percent."

You can find the serial number on the inside, driver side rear roof of your A.R.E. truck cap or cover.

In general, no. Most A.R.E. caps are custom fit for a specific truck. The height, bottom wrapover, front angle, width, length, and shape are all tailored towards one vehicle

However, for specific fitment questions, please contact us here.