I can confirm Fannin gets zero agency buys anymore, if they ever did. There is only one radio station there so it probably doesn't really matter except whenever a barter agreement is attempted.
Fannin is an odd case since they are in between 3 different markets, they have more in common with the Sherman-Durant market but are on the Paris EAS zone and get Dallas TV. However, if you are on the cable service you will get the Sherman CBS station but Dallas CBS on satellite. (Not to mention the Paris FM stations aren't all that easily received either.) If anything they should be in the Sherman Market, which I believe is a sub-market of Dallas as well.
I was told, as far as radio is concerned (and TV too), it all changed with 121 which made the area Dallas influenced. Apparently at some point they elected to be in the Dallas TV market but we're getting pretty far off topic!