I got to wondering about something else this morning, so I dug the decocking levers out of the UG P01 case to look at closer.
You can see where the black finish is worn off the right end of the left side decocker shaft when it was fitted to the right side lever. Nice and shiny and you can see either file marks or stone marks. No refinish after the metal removal.
If I insert the left side decocker lever shaft into the right side decocker lever and then turn the shaft vertical with the left side decocker down - and then shake it, the left side decocker lever/shaft will fall right out of the right side decocker lever. I mean, it's loose.
In the pistol frame it will not fall out if I turn the frame so that the decocker shaft is vertical, push the ejector downwards to release the shaft and then shake the snot out of the pistol. I have to push on the end of the shaft with something to get it to start to move, then I can pull it out from the left side.
I'm supposing, for the safeties, the force of the detent and spring (in/on the left side safety) pushing against the frame, helps keep the safety/shaft in the pistol when turned on it's left side, the ejector pushed downwards to get it out of the notch. Don't know, but it stays in place, too, and seems to require a harder "push" to get it started moving out. But I have not removed the safeties from the frame, put them together (like I did the decocking levers) turned them up and shook them to see if they fall apart.
I've fit two of these styles of safeties for a couple of my pistols. Fitting means metal removal from the left side shaft so that it will fit into the right side lever. I can't say how loose/sloppy the fits might be, I never did the same test on them I did on the P01 decocking levers.