Is it possible to match rear fog light with reverse light?

[Crackman 619]

I know you can match the reverse light with the rear fog light as demonstrated by colby on his R36 so the reverse omits a red light...

But what about making the rear fog light the same as the reverse light? I mean the brake lights are clear/white yet they produce a red light so can you change the rear fog light to clear but still make it produce a red light? or is this some legal requirement?

Thanks in advance for any info