Really there is no way to determine whether it is a hybrid anyway without dna testing at least according to the wildlife biologist I have spoke with.
Most of the hybrids in Kansas look a lot more like rios.
It would be my opinion that there are true rios but as stated you will never know anyway. The birds from south central to southwestern Kansas are going to be your best bet. Places like Byron Walker just outside of Kingman or Pratt sandhills area. Kansas also has a Walk in turkey hunting program but we are a long way off from seeing the 07 maps. Even the Cheneywildlife areaholds some decent birds.
Here is a rio I took close to the Byron Walker area.