if you don't mind me asking what about their process makes you say that? 
seems like a typical glue up process based off of other videos seen and articles i've read.
Touching the prepared horn with uncovered hands and grooves that aren't straight. There are other things as well but those are the main no no's. If you look about there are examples of delamed Korean hornbows.
There is best practise and then what works. Obviously their method works but I prefer to go a little 'safer' with my horn glue-ups to eliminate any problems.
Yes sinew round the nocks, they also cover that with birch bark sometimes or burnish and paint.
