That makes perfect sense. I did read in the military manuals that it is discarded and replaced during rebuild but now I know how it is staked.Ajm42 is correct. The purpose of the lock rings is to prevent the booster/bearing and/or the muzzle plug from shooting loose. You don't have to bother with staking/penning the band into the half round hole, a little Locktite will do the job. These bands were considered a one-time use item. It appears that your band is on backwards the thinner area is spread into the half round hole in the booster/bearing with a punch.
Lucky is right if using Lockite remember the Brylcream jingle "a little dab will do-ya". Do not ask how I know this. The tank gun and early M1919's didn't have the bands.Just bear in mind that you will have to, periodically, pull the booster to clean the carbon deposits. So, staking or locktite, whatever you use to secure it, don't over do it as you want to be able to get it back apart without making it harder than necessary. I just use a rubber strap wrench to tighten my bearings and rarely have one rotate loose under firing. Like my friend brassmagnet, maybe I am just lucky.... no pun intended!