Yes, it's certainly possible. We are in a long-term, ongoing effort to replace all of our
unlicensed assets, which are mainly map textures.
Are you on 2.3.x? Several textures have been changed since then.
Ideally, you would be set up on our repository (git) and could get the latest development files at any time. But it can be pretty difficult for someone who hasn't done it before (I required a lot of help).
That said, I think it is not a major concern. Updating textures at a later date will be easy if and when you feel it is necessary. I would say keep plugging away for the moment. If you're keen to get set up on the latest development version, hop on IRC and if someone is around who can help you they will do so.