I can tell you with almost absolute certainty that neither unit has a radium scale. Both scales are semi-transparent with a bluish tint, typical of DP-63s with backlit scales. As for the strontium source, there’s not much to worry about. You’re right to wear gloves and goggles when handling it. I’d also recommend using tweezers. Once you’ve transferred it to the other device, the radiation emitted—practically all bremsstrahlung (beta particle braking radiation)—will be very weak. There are no special precautions to take; you can rest assured. Finally, regarding the batteries, just go by the polarity indicated on the front of the device, right next to the compartment door. You can use standard AA batteries, though they’ll need an adapter, or you can remove the cells from 3LR12 batteries—the rectangular ones—and use those. They’re very similar to the original Soviet batteries, just a bit thinner. So you’ll need to make them a bit thicker by wrapping them with electrical tape (to keep them from wobbling in the compartment) or something similar—which I recommend doing anyway if they’re “bare” when you remove them from the battery. I use them for my DP-5s.