IMHO the only thing that could cause that type peening, that is peening toward the inside of the frame, is dry firing. If you look closely at the firing pin and its shape, it's pretty easy to see how it could happen. Too, I've noticed on my Uberti's that the metal around the firing pin hole is really quite thin.
The Uberti I shoot most has about twice as many rounds as yours and doesn't exhibit that type peening. I've never thought there was anything wrong with dry-firing centerfire handguns, but do so only occasionally. The peening is easy enough to fix; either carefully peen it back with a brass hammer or knock it down with a small stone. If you're going to continue dry firing you might want to have fired cases in the cylinders so the spent primers will support the tip of the firing pin and prevent the firing pin from contacting the area around the firing pin hole.