Thanks to everyone for the replies. After the fact, I located the image below, that illustrates the different roof lines for a 69 model 2-door. The top image, Custom Coupe, shows the same roof line that our 70 Caprice has.
So did Chevy drop the Sport Coupe altogether for 1970? Or was it just not available on the 2-door Caprice?
I'm sure this questions sounds goofy to some of you guys, but like I said, I'm new to big Chevies... just trying to figure out what's what.