Geddy Lee had a Rick double neck, as did Mike Rutherford. But Rutherford's had the guitar on top and the bass underneath, which would be my preference. I don't know if it has to do with weight balance, but the majority of guitar/bass double necks you see are configured with bass on top.
Wow - just wow! I don't think I've ever seen a lefty doubleneck before ever, let alone an unusual Rick. My guess is that the seller is either going to have a very easy or very hard time offloading it.
Sometimes, especially today when high dollar instruments seem to be much harder to sell, the investment/player usage/albatross equation seems to be so much more tilted towards the sea bird with these sorts of listings.