Did it clunk prior to the accident? If not, then something is loose. I had the front bumper cover off of my 2011 two weeks ago to install a GT type setup. There isn't much behind the cover that could "clunk". There's a styrofoam type piece that insulates between the metal bumper and the bumper cover; I could not see how that would "clunk".
I'd take it to the shop that did the repair, have the repair tech or body person go for a ride with you and have then check it out. That's of course assuming it did not clunk before the accident.
It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt.