It is absolutely possible to do that
You may have to dig into the plugin, but first check your chunks for anything with a name that looks like it could be related to galleriffic. That is commonly where the styling is done, directly in the chunk or the chunk can call a css file I believe.
It could be a bit deeper, but there is definitely some styling which is done and therefore a file that does it. The chunk is the best way, as css files for plugins may be a bit buried.
I would expect others could chime in, I am just providing basic info and don't know this plugin well.
