Hello, for this particular watch, I believe was passed on at Antiquourum as mentioned above
Then reappeared on a HK dealer, @PnFTimes on IG.
Then now being sold in UK i believe??
From my studies, I am led to believe that this specific type of dial shown on 3T watches is almost 100% dial swap, from DH(German military) watches.
Also for this particular movement and serial number, I did check with Longines heritage dept. and was NOT fitted with a black dial from the get-go.
So an assemblage, franken, whatever you may want to call it, but not worth the "black dial" premium, quite steep price of 9500 USD, in my humble opinion.
Regards.