I suspect what likely happened was the seller purchased an ex, but it arrived damaged, so Sideshow had them destroy the ex, but couldn't replace it, or could only replace it with a regular as the ex was all sold out.
So the seller destroyed the statue as instructed, but didn't destroy the exclusive sword hand. And as the regular version also has the axe hand as removable (unlike many regular editions, where the removable/switch out ex component is fixed on the regular editions), the seller probably frankensteined an 'as good as' ex by then combining their undamaged regular edition with the switch out sword hand and box from the ex that they had to destroy.
I pretty much went through the same thing, my ex arrived chipped and damaged, Sideshow couldn't replace it with another ex, so I destroyed the statue for refund, with the intention of getting a regular, but I kept the sword hand and made sure it wasn't damaged or destroyed, just in case the regulars were constructed the same...which I later found upon getting mine that they were. So basically I have a reg with a usable ex switchout sword, and a spare ex box from the destroyed piece (with matching foam that has a spot for the sword ex hand to fit), and I suspect something similar probably happened with the guy you purchased from.
If you don't care about the numbering/text on the bottom, it's as good as an ex anyhow, however the seller should have declared all that up front, and let the potential buyer make an informed decision on whether it matters to them or not, rather than just selling it as a proper exclusive.
I'd never sell mine, but if I did, I'd certainly be clear and up front about the exact nature of it. I'd also refer to it as a regular with usable exlusive switch out rather than just calling it an exclusive version, but yeah, anyway...
