I think you could get $40's for your car. For some reason 68 model year 911's are not as sought after as the 67 cars, due to little things like the side marker lights, elephant hide door panels, and non chrome bezel gauges, sugar scoop headlights instead of the sealed hellas.
The L model was essentially an S without the motor
- kind of the most important thing. But your car should have the S suspension and brakes, as well as rear sway bar. It looks like you have SC high back seats in your car which isn't a plus. Your L car should also have come with a complete set of 5 1/2 Fuchs instead of the steel wheels. I still think your car is worth $40's. With a set of deep 6's, some original early sport seats and a set of Cibies maybe high $40's. But all of that stuff will cost you another $10k....