That bass is so gorgeous, I'd like to take it from behind. (in a lecherous voice) It is string thru, ja?
It's the Ripper Gibson should have made and the world would be a different place.
Going back to the G-3 twins: It really is hard to decide. Both look good, my hunch is that natural G-3s are perhaps a tiny bit rarer than black/ebony ones, but ultimately they were the two most prevalent fins. If weight isn't an issue to you, you could always sell the alder one and state in the auction text that this is "one of the lighter, alder body ones, not the regular maple millstone", because to many people weight of a bass is an issue, especially the elderly folks who frequent this forum. It might - together with its pristiner looks - fetch a higher price because of that.
Or do indeed play them for half a year and find out which one is better in bed in the long run.
Uwe