I put on the 4100 series on my F350. I ask for 5100 but after the tech looked them up he said they were designed for trucks with a lift kit and the 4100 are without lift. I have read that people have put them on non lifted trucks.
This is from Blistein website....
BILSTEIN 5100 Series Shock Absorbers are designed specifically to help your lifted truck, Jeep or SUV reach its pinnacle in ride performance, while supplying the correct tuning and length for your specific lift.
Edited - That should read 4600 series not 4100 series.