You're right, Skip, but the 1984 I had didn't have that protection ,,, it was just smooth like the Testors body I'm using.
The Hasegawa Porsche 944 Turbo kit I'm using to build the 1991 S2 I had does have that protective coating molded in, as you can see below. It even has the smooth piece above the rough area protecting the rear fender from chips.
Thanks for noting this little piece of 944 history!
EDIT: I found a photo of my 944 and it did have the stone guards, also looks like the rocker bumpy material.