Can GUID's in packages change during importing/exporting a package?

I'm making a generic UI system that I want to use over and over. I reference another package's assets that I made. I import the asset package first, before importing my UI package.

I have not noticed broken links between my prefabs and the assets I'm referencing. However, I am worried that it will break (GUID's change somehow) and do not want to continue making a basic assumption, before I write a lot of code/make tons of prefabs.