Look at the intake. If you have 2 separate hoses leading from the throttle body to the air box it's S/D if you have a single hose which is bifurcated at the throttle body end and which leads to an aluminum clyinder mounted on the end of the air box it's MAF. The aluminum cylinder is the mass-air meter.
If you're expecting any real HP gains out of the K&N save your money. The gains from the less restrictive airflow are largely offset by the higher air temperatures. Thry work well on some other models where they provide a high flow cold air intake but on our generation of F150, they mostly add intake noise.