Yes, you can instruct WebLogic to use an override version of JSF.
And originally this was done by including the JSF implementation library you wanted in the WAR along with some special directives in web.xml.
I just checked the latest docs, however, and it looks like they're no longer doing it that way. From what I can see, WLS now comes with legacy versions of JSF pre-installed and I think that you can also install your own JSF implementations in the WLS server common library set instead of in the WAR. The decision on which JSF implementation to use is now done in the weblogic.xml file rather than the WEB-INF/web.xml file.
For more information:
https://docs.oracle.com/cd/E17904_01/web.1111/e13712/configurejsfandjtsl.htm
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.