This bull has been emailed around everywhere lately, the story on the elk herd can be read here:
http://www.rmef.org/wapiti/pages/05spring/texas.html,
In order to hunt elk in Texas, you would only have buy a hunting license, and have permission to hunt on private property. No season, no bag limit, no restrictions on weapons, bait, etc., anything goes with an animal considered an exotic, as long as you posses a valid hunting license.
The bull is not eligible for entry into Boone and Crockett because it comes from a state without a regulated hunting season, and elk are no longer considered game animals in the state of Texas.
Occassionally elk may wander into Texas from New Mexico, but very rarely. This herd in Alpine was released by private ranchers and is not native to the area. However, if that were the only criteria for the books, only a select few mountain ranges in the entire American west would have record book eligible elk, as a majority of wild elk throughout the west were re-stocked at some point in the last century.
I've heard that this was a "fed" elk as well, but the range that the herd inhabits has had extremely good range conditions in the last 2-3 years, with well above average rainfall, so that the possiblity of the bull having naturally grown antlers of this size isn't out of the question