First post, by precaud
The answer is a qualified yes. As long as you have clear access to the side of the chip that has the terminals that need to be exposed, it is actually quite easy to do with the chip in place. You only need to be able to see what you're doing, and get the Dremel tip into the body of the chip without touching anything else. The material in these Dallas chips is quite soft, so the Dremel is easy to control..
Not having to desolder the chip turns this into an easy process. I did the DS12887 in an Intel Plato board this afternoon in a little over an hour. If it weren't for the 1/2 hour cure time needed by the epoxy, it would have taken about 40 minutes.