If a component has attached pattern, this pattern was stored in component library. Component library is self-dependent and contains all necessary data. Therefore it doesn't matter what library did the pattern come from.
That's interesting. I didn't realize that the pattern got stored in the component library.
The reason I asked the question is that I discovered that there are several SOT-23 footprints. Some of the ones in the SMT library have pads that are too small for hand soldering, while the SOT-23 footprints by the same name in the SOT library have bigger pads that are easier to solder. I was going through the libraries trying to identify the components that had the SOT-23 pattern with the smaller pads. You can't really see the difference by viewing the footprint in the attached pattern
What I ended up doing was copying all of the parts we use into as new library and manually changing the attached pattern to the one that works for us.
If you can think of an easier way to do this it would be great, since I have many more components to go through.