Just some advice on the Genetic Testing. I do genetic testing on most of my horses for various reasons. If you want to prove that this is truly Max, the only way to do that is Parentage Verification, which means you have to have both parents tested as well to prove that this particular horse came from these particular parents. Just testing Max , if the parents are not DNA typed will prove nothing really. If his parents are both registered (and I assume they are since he is) you may be able to call the Registry Association and ask if they are dna typed.
ROPO, I would be proactive here and go ahead and check this out, if you explain the situation and especially to APHA, if I remember right that is where he is registered, they may go ahead and give you the information , I would also speak with Member Services, a girl named Karen there is awesome. I hope this helps some. Also contact Shelterwood Labs, they do all my DNA testing and are inexpensive , you may explain the situation to them and see if paying an extra fee can get the test done quicker, it never hurts to ask.