Since Golden Freddy is not Freddy or meant to be a variation of Freddy, I think he should get a name that makes more sense.
Since he's Fredbear, let's think of his name as (Adjective) Fredbear right now. Since he's an old, rundown version of Fredbear, let's look at another animatronic like that. Withered Freddy. While not as old, he is still a replaced Freddy that is old and rundown.
Now you see what name I'm trying to say we should call Golden Freddy. Withered Fredbear. I know nobody will call him this, but I will (thank you for reading!!!!)