No, they are different but related areas of expertise. One gives some level of insight and ability in the other, but expertise in one does not give expertise in the other. Not that one couldn’t learn both, and it wouldn’t help, depending too on what your design parameters were.
Nowadays, computers and megacorporate profit margins influence car design to a great degree, in ways they did not in the past. Computers do lots of calculations, and are involved in the design and engineering of modern cars. Also involved is creating an expensive product that passes modern legal regulations, and that is engineered and designed to break and require repair by the company’s own proprietary equipment, or that is only feasible by replacement with the company’s own expensive replacement modules.
I just bought a 1988 VW Fox, a discontinued line and type of car, and I was amazed by its simplicity and efficiency. The thing gets like 40 MPG and may run to 300,000 miles, and just looking at it, I can pretty much see most of the parts and they are mechanical and functional, and look like they could be fixed or replaced or swapped for something else (like a cool 1970’s Jaguar I also saw which has a Buick engine swapped into it successfully). Looking into a modern car, it’s full of air bags and computer modules etc., and there’s little to no hope of replacing much unless it comes from the factory, and unless the mechanic has a bunch of very expensive computer equipment from the manufacturer.