Copy Item Link Stickiness

When I do a COPY ITEM LINK I get a URL with something that looks like a UUID. Is that URL valid regardless of where I move the referenced item (e.g. between databases)? I think it is, but just want make sure there are no other conditions that I need to be aware of.

It is. You can move the item to other groups or databases or rename it, this does not affect the link.