My 1970 L78 had GM Canada documented optional F41 suspension.I've heard of F41 suspension on a caprice...I thought it was typically for the 9C1 police cars. I have an 89 caprice, it's not a police car but has a rear sway bar but I think it's because it has a tow package. I wasn't even aware they were available on Novas.
Now you've got my curiousity going. I'm going to have to peek under and see if mine has all of that.