Sinister- The short answer is "Yes, you need moon clips."
The long answer is that the revolver will work without them. It has a shelf in the chamber upon which the case mouth will headspace, just as the case mouth of a .45 ACP headspaces in the Model 1911 autopistol. The extractor won't work that way, though; you'd need a pencil to push the fired cases out from the front, one at a time. Still, if you did happen to be stranded on a desert island with a metric ton of .45 ACP ammo and no clips, being able to fire but having to poke the empties out is much better than not being able to fire at all.
The even longer answer would go into detail about how you can get full moon clips, that hold six rounds; the original half moon clips, first introduced in World War I, which hold three each; a plastic version (I think); and even a two-shot version, so you'd have to load three of them to get a full cylinder. Or at least they did make those at one time. I'm not sure if they still make the two-shot version. I don't know what the advantage of those over the three shot would be.
Or you can get .45 Auto Rim cartridges. They are what they sound like, a rimmed revolver cartridge which is dimensionally the same as a .45 ACP from the rim forward. They were designed just so there would be a cartridge you could use without moon clips in the .45 ACP revolvers which normally required them.
You have to be a bit careful with the .45 Auto Rim, since at least one .45 ACP revolver, the Taurus Stellar Tracker five-shot, couldn't chamber the Auto Rim. But the Smith 25, 625, etc. will. So will the Colt Model 1917 revolver the Army used along with the S&W Model 1917, for that matter.
