I think whoever buys it is getting punked!
Look at the pics more closely.
The loco has in paint AEC(Atomic Energy Commision...Predessor to the Nuclear Regulatory Commision)and a printed piece of paper glued to the sides with WNBC Ch-4 on it Where's the peacock? If it was done from Lionel for NBC bosses, youd think Lionel would of done a better paint job then a piece of paper glued on to an off the shelf loco. Also...In 1959, Lionel was having fiancial problems. Giving away something like that for nothing would be stupid.
Second....Does that look like a box thats been sitting around for almost fifty years? If it was stored in that box, moved countless times, there would be some sort of damage, fading. looks too new. Though, it could be a new box, made for this item(Made to look original?).
The base maybe authentic. But thats the only thing thats real, and even thats not worth $5000.
But..If its for display, why would you leave the track connectors on? The rest, in my opinion is faked. The original loco that came with the base, may have been lost, ended up on someones layout from an estate sale, or in some kids sandbox.
I agree with Jim.....Junk!