That's so freeking funny.
I just went out there too (exact same spot) and no matter how much I tried to convince that nice man with the weapons, he wouldn't let me take the picture, nor would he take it for me. I pulled out all the stops, mentioned that I was former military and had previously held a security clearance, even mentioned that I earned special ribbons for my actions. Even said that no one would ever know and it was just a picture of a helicopter (a damn cool huey from nam). Said that if he'd let me drive up to it I could make sure that I didn't get anything but my bike and the helicopter in the picture.
He didn't bite. No joy.
btw: It's not just the National Guard Armory but also a Lockheed Martin facility...me guess tht they stock more than just the small caliber weapons that the guards were carrying.
Here's what it looks like (minus the motorcycle):