First and foremost... all 1pc cobra r bumpers are fake.
but the version you got is just different. I've seen the urethane ones that have the 2 (or was it 3?) pillars in the center opening. I had one for my '96 had the 2 i believe.
The only "bad" thing i can see with 1 pillar is that it won't provide enough support and may sag.
There is only 1 guy on ebay that i've seen shows 3 different pics on the auction. 1 is of the real cobra r kit on a red 99+ (which is the cobra bumper plus the cobra r splitter attached to it), a black r bumper with 1 pillar and another one, i think..that shows the 2 pillar but is a 1pc ureathane kit.
If your not happy with what you got, i'd contact them. Remember, this is money you spent.