That is a gorgeous buck, no matter who his parents were! If he isn't skinned yet, take a photo of his tail and also his metatarsal glands. It is said that hybrids have distinctive metatarsals that are half way between a WT and a Mulie in shape. Ditto the tail.
I had him already skinned when I made the post but will go check the gland on the legs. The tail looked normal to me. I will take a pic of the glands later when the sun gets up.