Rebecca gives Bobby an old legal document relating to Southfork Ranch. Thd document lists the ranch's address as being in Parker, Texas. However, in the original series, Southfork is set in the (fictitious) area of Braddock, Texas. Parker is actually the real-life location that the ranch is situated where the show is filmed.
The mineral rights were already known about in the original Dallas. Miss Ellie told the family that she owned them when J.R. used the ranch for collateral. It was also talked about by J.R. himself when Carter McKay was trying to force the Ewings to sell section 40 to him.(secretly for Westar)