At that exact time, the Celts at Hallstadt were making fabric from exactly the same material (European sheep wool), using exactly the same production techniques and this resulted in clothing and designs exactly the same as at Hallstadt. There was, as yet unexplained, a connection. (Elizabeth Barber, Mummies Of Urumchi--Victor Mair, The Tarim Mummies)
Ah, right you are about that my friend. Hallstadt was a boomer to be sure, but mostly later one. The link you refer to is an excellent and I think important one between some Chinese finds and the Celts.
I was thinking of the time of David, which was ~1000 BC. The "Celts" at Hallstadt at that time were of the "Proto-Celt" variety. Related for sure, but displaced in time from the big Celtic invasion from the East which occured later.