I had one of these also. The reason the bolt handle could come off was it was silversoldered onto the bolt instead of being welded. The silversolder wasn't strong enough on a couple of guns and came apart would be my guess. Take a look at the bottom of the action and you can see more of the solder. My dad bought two of these guns in the 50's and they were used for 50 years with no problem. I think you could probably have the handle taken off and welded back on and be safe. But, I can understand why Sears can't tell you to do that. Law suits up the wazoo.
Ed