Nice buck! NTO I've seen people fined for tagging them like that though so be careful. I think once the phone call is made it doesn't matter so much anymore, but they used to have very specific tagging instructions for tagging the tendon on the hind leg, not the antlers. Back when you took them to a checkin station, they got pretty upset about that, but it may not matter anymore. Just don't want you to get in trouble for something stupid. But the tagging instructions are, or used to be printed on the tag. I haven't bought mine yet this year.

I just went to MDC.com and checked, and yes it must be tagged on the tendon of a hind leg. It really doesn't matter to me, but I dont want anyone to get in trouble over something this crazy, and as I said ,I've seen people at the old check in stations fined for this. Just a heads up in case your picture ends up being seen by a game warden in a bad mood.
I personnally think tagging the antlers is fine, and a good way to ID them in a locker situation, where you don't want to get heads mixed up. But I guess the Missouri Dept. of Conservation is probably more worried about the deer keeping it's tag through processing as the head is usually cut off for the hunter before he leaves, and the tag should stay with the meat.
Anyone else reading this and hunting Missouri this year should also take notice and possibly check it out for yourself by looking online or on the back of your tag, which is where it used to be printed.