There are no orange Flinties in my experience.
Under UV light Flinties just lay there wondering what you are doing. Flinties are opalescent so white light is the way to ID them
Brown (light reddish orange), Green, Blue, Red, White and Yellow are the colors that you may find. The brown ones seem to be the most common. White and yellow are a hard find for me.
Yours look yellow to me. Shine a penlight through them. If the light does not penetrate, they are not Flinties. If the light does penetrate it should show through the marble as a reddish orange instead of white.
Marble—On!!