Loaded texture parameters?

If I load a 2D texture with these parameters.
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

Then later on in the code I wish to change to these parameters for the same texture.
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

Is that a valid call, and will it actualy change the rendering of that texture? Or will the first values always be used?

Just be sure to bind (make active) the texture that you want to change the parameter for.

DrawCb()
{
   ...
   glBindTexture(GL_TEXTURE_2D, textureName);
   if(usingLinear == true))
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   else
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   ...
}