To clarify, the Dead Sea Scrolls are not forgeries. These specific (what were though to be) copies/additional fragments that this one museum bought are forgeries, but the Dead Sea Scrolls are real.
I doubt anyone was confused on that point, but for what its worth: One of the earliest carbon dating tests was carried out on November 14, 1950. This was on a piece of linen from Qumran Cave 1, the resulting date range being 167 BCE – 233 CE.