I have the front license plate holder, but haven't installed it yet: I don't want to drill holes in the front of my roadster, so I'm using the "honor system".
I live in Texas, and they don't check for a front license when you get your annual inspection. I keep the unused license holder handy, in the original Chrysler box, and when I was stopped a few months ago for another reason, I explained that I had recently learned that a front license plate was required, I ordered the holder from Chrysler, and it arrived yesterday, "...and I guess that's just a day too late".
The trooper accepted my story, and I ended up with two warnings - no court appearance required. If I can avoid that trooper for a bit longer, he will (hopefully) forget the incident - and if not, I'll resort to "plan B".