Not a real CSL, but a car built by Alf Gebhardt. Alf owned BMI, hence the windshield banner, the Tulsa, Oklahoma BMW dealership back in the 70's and 80's. Interesting guy with a lot of BMW racing history. It was always fascinating to go to the dealership and see what cars he had around. I saw my first M1 and M1 Procar there along with other gray market stuff he would import.
Car still exists and is owned by a long term BMW CCA member.