Hey, 3turkeys, welcome to the forum and thanks for posting here about your NM hunt. Great to hear that you had a good hunt here in our state. We do have some really good public lands hunting, especially in the Lincoln NF.
The buff coloration on the tail feathers you described is pretty typical of the birds here....at least in the southern part of the state. For whatever reason, the Merriams in the northern states tend to have more white in their coloration.
Our birds are supposedly pure Merriams, but I am not sure there has really been any serious genetic testing done. I can tell you that the buff coloration has been the norm for the past forty years I have been hunting here.
Unfortunately, Rios have been introduced in recent years into a couple of places that will eventually result in contamination of our Merriams genetics. Two of those introductions have occurred north of Ruidoso, so it is not out of the question that the birds you harvested in that area might not be pure Merriams. The ones further south (Sac's) were likely to be pure-strain Merriams, but they still do not have really white feathers.
At any rate, I'm glad to hear you had a successful hunt in NM, and once again, welcome to the forum.....hope you stick around and become a regular contributor.