Not sure about 66, definitely looks like 65 so its very possible but I can't make out the first digit.No 63 at 0:16, another number ticked off.
Edit:i think the video also feature x6 maybe 66? at 0:16 and 65? at 0:17,33
Even so we have been quite spoiled with J-15 serial number spottings since the first sighting of Batch 3 in October 2020. That's 20 in just around 3/4 of a year and has done a lot to raise our estimates of the J-15 fleet in a very short time span.
For now I will stick to the 24 Batch 1/2 + 10 3X serials and then the from 60 starting J-15 serials as the acknowledged ORBAT however a part of me is still curios whether or not there are some 4X, 5X and remaining unspotted 2X Batch 3 aircraft.
I am even more curios about production rate given that the Batch 3 production can't have started too long ago.