I also got confused by the COMPONENTS and COMPONENT keywords and their relationship.
Forget the stuff I mentioned about find_package. As Craig wrote correctly the COMPONENT keyword in the install command only effects installing the specific components / targets but has no implicit effect on find_package or how it uses components.
The COMPONENTS keyword of find_package is just some kind of hint for the underlying export file and it is up to that file to decide what to do if a component is given to the find_package command for the specific library.