The linked article makes it sound as if though 200 grain .38's were a passing aberration. The heavy round was around, factory loaded, for over 50 years. I have never read or seen anything that made me think they were developed for vehicle penetration either. Ken Waters also had a really great article on the .38 special. It is all the more interesting because it was written a little closer to the beginning of the .38 special. Here is a link to a pdf file of it.
https://riflemagazine.com/magazine/PDF/hl3partial.pdf