That appears to be maple. Maple is one of those species that changes color over time. It turns yellow. If you start sanding, you will almost certainly get through the yellowed outer layer and reveal the bone colored natural wood. That is not a problem in and of itself, but it will force you to sand every inch of it unless you want different colors on different pieces.

Can you tell if the existing finish is a film building finish or some sort of penetrating oil? If it is a film building finish I would scuff it up with the 220 grit Scotch-Brite sponge and then spray on a coat of aerosol Lacquer or polyurethane varnish. I don’t have good advice if it is a penetrating oil type of finish. I played with that years ago, but gave up on it because of its lack of protection to the surface.