The one I had purchased at O'Reilly originally had the 5 oval holes. When I took it to another O'Reilly to check their supply, they were as confused as I am.
I told them my concern for authenticity and they pulled every 2124 filter off their shelf and out of the back. We opened each one to check the hole arrangement. Each had the 5 oval holes instead of the 8 round ones as they showed on their own website.
Fortunately, no one else was in the store and waiting for service while the 3 of us stood there collectively scratching our heads while looking at the photos on the website and staring at the filters scattered across the counter. Were I interested enough to do the calculations, I could figure out the maximum flow potential of the 5 oval holes vs the 8 round holes, but that is not good use of my time. Someone at Ford or Motorcraft or whoever makes the Motorcraft filter (Purolator?) should be able to provide a quick answer to state clearly, "Yeah, that's one of ours... It's authentic."
Even if the media inside is the same, why the departure of the "same" filter between the dealer channel and the parts supply channel? Maybe there is a clear answer out there somewhere, but I've not seen it yet.
It's all a bit frustrating.
I returned the filter I had to O'Reilly, went to Advanced Auto Parts to see their supply, found their's the same 5 oval holes, left them scratching their heads, went to Napa, learned they don't carry Motorcraft, and now, next step will be to just go to the Ford dealer and see what they have. In the end, we will likely learn the 5 ovals are fine and the media is the same. For now, paying for the piece of mind is okay with me until a clear, concise answer emerges.
Perhaps it is all just a brilliant marketing conspiracy to compel nervous-nelly, anal-retentive, recovering-engineer, shade tree mechanics like me to pay the padded margins for the same functionality/efficiency of the Ford parts department.
For now, I can only wonder...