The 442 Pro comes factory cut for moon clips. This is the way to go. It is NO LOCK for one thing. Next you can load it with: Loose Rounds, Quick Strips, Speed Loaders, or Moon Clips. When doing the moon clip cut, they leave a ring on the outside rear of the cylinder for the 38 rounds to head space on when not in a moon clip.
If you do not choose to use moon clips, you do not have to, it will still load like every other 38 J Frame S&W. I personally like the added option of moon clips. The moon clip 442 is not all that expensive either. Something like an extra $30 I believe. Probably worth $30 to me to not have the Lock.
The J Frame 38 Special does have a couple things to keep in mind when using moon clips.
01. All 38 Special ammo is not made alike. The undercut at the rim on Winchester and Starline is to tight for moon clips. Use Remington or other brands with a larger cut.
02. The 38 Special J Frame moon clips are .025 thick, or Thin might be a better term. They are not as robust as 45 and 10mm moon clips. You do need to treat them with some care not to bend them. A custom single post North Mountain Carrier might be a start for carrying two reloads. Use a moon clip loading and unloading tool, the tools will keep you from bending the clips.
If you get to using moon clips you will likw them. And like I said above, you can still load with Quick Strips, Speed Loaders, and Loose Rounds, like you would any other J Frame 38 Special.
Bob