I bought that reproduction of Sword of Seals. unfortunately, it does not use this patch, but rather the old 'Sword of Seals' one.
There is also a bug I experienced. Whenever I save the game it freezes for a second, then goes back to normal, but the sound effects are very quiet. Leaving the music the same volume, but way louder in comparison.
This glitch is common among every reproduction of FE 6 I looked at. It would be mentioned at least once or twice in the reviews from different seller's listings.
I did notice that when I looked at the seller's page for the one I bought, he had a listing for a repro with the 'Binding Blade' patch instead. It's the only repro so far I've seen that uses this patch.
This is it: https://www.etsy.com/listing/250038690/fire-emblem-the-binding-blade-fan-made?ref=listing-shop-header-2
I still wouldn't recommend getting either of them. Like what Bookofholsety said, it's shady and you don't know how poorly it's made and what kind of problems it would have. Not to mention, as of right now, while I'm posting this, there hasn't been any reviews yet for the repro I linked using this patch.