Biggest problem is you are TOO close to it! You forgot the 10 foot rule. Seriously, when you zoom in on most anything that close you are going to see every little defect. If the stuff isn't literally falling off, forget it. Paint the whole thing with linseed oil or similar and go with it. If there is stuff loose enough to fall off, just brush the loose stuff off, then paint. After a while you wont even think about it. I grant you the condition is less than ideal but is it worth getting into a battle with the D&P or your outfitter over? I had some critters come back looking pretty dried out last time for whatever reason, so I just slobbered linseed oil on them and forgot about it. They look great now. I painted some horns years ago with linseed and they still look good.