I agree with some of the others here. In the US, being a .307 will definitely make it a not really sought-after rifle. Blue book value would apply to someone who wants it for a collector piece or for the increased ballistic power, but would probably be a dickering point for most everyone else.
.307 is an oddball that never really caught on over here. And YES, it does kick like a mule in a little 94 carbine! Personally, I think the .375Win has less recoil...to my shoulder anyway.
As RJay said, it was a rimmed version of the .308 that Winchester schemed up for their "new" angle-eject version of the 94.
I can understand it's popularity in the countries that prohibit .308 ownership though. A neat "loophole".
Also, if you've noticed, the .307 was chambered in the "Big-Bore" version of the the 94 which was a beefed up action that was introduced for the .375Win but later the .307 and .356Winchester (a rimmed version of the .358) were added to the lineup.