Just got myself a 93 2.8 Turbo Diesel F78 Rocky. I'm so happy with it!!

Took the air filter element out yesterday and saw a plastic object around one end of the filter (Closest to turbo) where the cold air intake comes into the airbox. It sleeves around the filter leaving a small gap between it and the element. Its a normal paper filter. The end of the plastic 'thingy' has fins all the way around which looks like it circulates the air flow around in the housing. Sorta hyclone-ish technology.
I'm wondering if this is a stock item, or aftermarket.
I just think its blocking half of the element, and the air has to travel further in the airbox until it reaches the filter.
Confused....
Nick.