Richard,
Those grips do look great! I actually have 2 stainless mustangs one of which my wife carries now and then and I used to carry back in the 90s. Never had any issues, accurate for their size. Great little guns in my opinion even though they are 380s. I do remember a time when I was out plinking and fired at an abandoned refrigerator from the side and the little 380 penetrated both side of the refrigerator and then through one door of an old car that was behind it. I think the 9mm short is actually under rated, especially with modern ammo.
I also have found the Mustang to be very accurate for its size. Once at the range, just for grins, I ran a magazine through it firing at plates from 50 yards. No one was more astonished than I was that out of six rounds two were hits.
Back in the '80s, an acquaintance of mine purchased a Mustang at my recommendation. A few days later he called me to complain that it was a totally inaccurate pistol and invited me out to his farm on the Chesapeake Bay to try it for myself. We met there, went to his range, and set up a target at 15 yards or so. My first shot was in the 10 circle. Knowing enough to quit while I was ahead, I activated the safety, handed the Mustang back to its owner, and said, "It looks fine to me."
And the stainless steel version of the Mustang has no problem digesting the modern higher-pressure loads that, as you observe, can give the 380 ACP (9mm short) some rather impressive ballistics.