My first assumption? It's real.
After carefully reviewing each and every aspect of the aforementioned clues to it being a fake (shadows , splices , etc.)? It's real! Call me an optimistic , but for me it's real until proven fake.

As for the shadows? Dont expect normal shadows as you'd see in a normal circumstance of a pic at night where the flash is casting the only light source. In the pic you can see the light is luminated on the back of the cab.

As for photoshop splices? Show me. I see none.

As for grabbing the base of the antlers? It's pretty common to try and grab the antlers in a spot that wont obstruct the view of any of the antlers. Which is what I would do in that situation.

As for the pic and story being all over the hunting boards? Guys and gals , there are far more hunters who have never visited a hunting board than there are those that do.
I've seen some awesome racks in my day that were just sawed off and nailed to a wall in a barn.

Thats my $.02