The 442 does not necessarily accept moon clips. The main difference between the 642 and 442 is the finish; the 642 is a clear "stainless" like anodizing, the 442 is dark.
There are variants which are indeed cut for moon clips. However, the only moon clipped wheelgun I have is a 327... eight rounds of .357 in an N frame is a little different than 5 of .38spl in a J. Generally, though, it works well. Still, I'm not sure it's THAT much better than a good speedloader.