And the city has no need of sun or moon to shine on it, for the glory of God gives it light, and its lamp is the Lamb.

The only problem I see with the light in Genesis 1 and Revelation being the same (lamb). Is though in Revelation we know the lamp is the "lamb", the Genesis account does not say this.
I think the only thing certain we can say about the Genesis account, is that is was something God put in place.