Yes, these guys from FNaS-Swap (Specifically the og one CyVap was working on before the ownership was passed down to Tuna years later) are gonna be skins for their original counterparts.

With that in mind, coming up with a skin for '15 Golden Sonic is not easy btw.

We could use Swap!Luigikid (or '08 Luigikid as it's called) from NIGHTFALL AT MARIO'S, however I'm pretty sure we'd need Tuna's permission to add him, and on top of that, we'd have to come up with which character could Dear Brother could be a skin for because it doesn't really seem right to leave out 1 out of the 6 main antagonists from NFaM.

We could also use Swap!Bew, but for obvious reasons (that being the character's obvious association with a groomer), we're not putting him into the game. Even if we wanted to, the character is blacklisted from being put in any FNaS projects in general.

We could also use Thorn, which is technically the official FNaS-Swap variant of Golden Sonic, however that character is made for modern FNaS-Swap by Tuna rather than the og one by TheCyVap, and since this game is kinda going for more of a classic-FNaS theme or something, I don't necessarily think it would fit the definition. You could argue that we could come up with some kind of design for Thorn to better represent the og FNaS games, but that would just take time and I'm pretty sure the only difference would be the color palettes. Even then, Thorn appearance-wise is just Golden Sonic if he was possessed by Amy instead of Eggman, instead of having the entire character being swapped with someone else.