I doubt that it will "stick," but since I haven't gotten that far, I don't know how important it is that it sticks. In machining, if you put a hole in the wrong place, the piece usually goes to the scrap barrel. Sometimes you can get away with press fitting a plug in something non-structural, but that's precision machining, not foundry work.
I spend most of my time across the hall from the machine shop, soldering. Solder is a mixture of tin and lead, and a lot of people have the idea that it's sort of like hot melt glue. It isn't. The solder has to bond the parts at the molecular level, and to do that, the parts have to be hot. What you propose is filling a stone-cold hole with molten lead. There's no reason I can see for it to bond.
Now, having said that, I've learned from vast experience that I'm often just plain wrong about things, so I'm perfectly happy to be corrected on this one, too.
