I asked the seller a question when this first popped up. He bought it this way, the prior owner had the work done. We put our heads together and figured the PO wanted the bell to resonate more, so moved the brace mounting point further back.
Since the bell tenon and brace are all one piece, it would be pretty close to impossible to do this accidentally. There's no socket on that tenon. You'd need to undo a hard-soldered joint at the tenon, change the angle of the brace, remove a lot of solder stains, and re-hard-solder the brace on the tenon. It's actually a nicely-executed repair.
Now, as to the utility of it, I have to believe that King had a reason for wanting to shift the brace flange forward instead of backward. I don't think "intuitive physics" is going to create a better sound in a horn that was engineered a particular way by the factory.
Wasn't there a horn for sale years back that supposedly belonged to Dick Nash that had the brace on backwards like this? (Or maybe it was Dick Shearer?)
*And I sure as hell wouldn't drop $1750 on a 2B that didn't include the coffin case.
My Strickler has a flipped brace. Seeing as I've only seen two other Stricklers and did not have a chance to play either one, I can't say if it makes a difference.
Consider this: if you took the horn to a really good tech and they flipped the brace, they'd also reassemble the horn so that there was minimal residual stress. How much of any difference in playing is due to geometry and how much is due to stress-free assembly?
I heard it was a mod some did to Kings for changing its resonance or response or lining overtones differently. Same reason any brace placement is important.