Obviously official sources will soon be able to say for sure, but even though I have little knowledge of Buck history I want to throw my thoughts out before you think about bidding even $9.99 for this knife.
As far as I know, a Buck 307 has been a 3 blade stockman with a black handle and silver bolster for a long time. Searching for "Buck Wrangler," also shown on the box in the photo in addition to the 307 number, will briing up a picture of the same stockman on google, not a lockback. So at the very least they have the wrong box.
Looking at the knife itself, it looks like the work of Camillus or worse. In the first picture, note two things:
1. Bad fitting of scales to bolsters. I have seen a few Bucks from decades ago, and they are better than this.
2. Look at the blade bevel just before the tang. See how the previous stage grind lines show through closer to the tang? Typical of crappy finishing.
The finer details of the shape of the lockback mechanism don't match with virtually every Buck lockback I have seen. They usually have the heel-looking part of the tang hang over the end of the lock bar when closed. You can't see directly in these pictures, but the length of the lock bar on this knife makes it look like this isn't the same, or if it was we might see the rounded back end of the tang stick out of the bolster when the blade is closed. It also looks like the end of the blade's spine is further forward of the pivot pin than most bucks.
Unless someone chimes in and says Buck made this knife for Winchester without markings and put it in a marked box, I would say nothing about it looks like a Buck.