My house built in the 70s has some oak flooring that has half inch dowel plugs at the end of each strip that I would like to get rid of. It appears that they are of a different wood, possibly walnut. There are probably 200 of them. Can they be sanded out? Stained to match? Removed and replaced? Or do I need to tear it all out an start from scratch?

the only way I see is to stain the floor the color of the plugs. They cant be removed and replaced or sanded out.

You can drill out the walnut plugs and insert oak plugs then sand and refinish . Just make sure you twist the new dowel to line up grain.