Basically no.
But to do a skin you should write a CSS for the XHTML that LibreSource generate and register it in the file LS_ROOT/Src/LS-Client/Default-WebApp/WEB-INF/libresource-web.xml
Your CSS file should be packaged here LS_ROOT/Src/LS-Client/Default-WebApp/Style/XXX/xy.css
Seb