Without pictures of the gill plate it is hard to tell.
I have one orange Wakin Goldfish that accidentally got it's gill plate caught in a net and it tore the gill plate off. The fish recovered, has grown up, and has been doing great for 3 years in my outdoor pond, however the gill plate never grew back.
had a red empress fry that was born without and had developed fine no issue just blood red gill exposed to the world.