Ron's is a reputable dealer that frequently advertises high grade and unusual/uncommon firearms, so they probably have the provenance documentation to support their claim.

I have always been under the impression that Eleanor O'Connor was on the short side and that rifle looks to have a pretty standard LOP.

When you're paying a premium price for the story attached to an item it has long been my rule of thumb that you need provenance, provenance, and more provenance. Without provenance a great story, no matter how true, is just another story about the big one that got away.

I've bought a couple of firearms from Ron's, all unusual and premium priced, but I've never seen any of them for sale elsewhere.