Great buck!! As for the antlers, well, they are antlers. They don't always follow the norms. There are both mulies and whitetails in the Repuplic area and it's possible that there has been some cross-breeding. Most whitetail-muley crosses I've seen in Colorado have hide coloration overlaps as well. A muley with long brow tines and an odd colored tail, or facial coloration variations. This buck looks like pure muley though from the photo.
Here's my 2009 blacktail with a similar antler configuration. He was a clean 3x3 with no brow tines last year. This year he just added another tine off the mainbeam on the left side. It's not all that uncommon, really.