A goat that dies of entero has purple striations on the intestines. I haven't heard of signs of polio that can be seen at autopsy. I am not saying there aren't but at any rate my vet never mentioned any to me. With suspected polio, your best bet is to treat it. If it improves after a few doses of thiamine, you know that is the problem. If it doesn't, polio probably isn't what is wrong, but in any event the thiamine will not have made the animal worse. From personal experience I can tell you that a lot of vets don't recognize either entero or polio in goats. Nothing against them, but their training in vet school about goats is usually sketchy at best.
If I were you, I would give every kid a dose of BoSe for white muscle and a shot of CD/T as soon as you get them home. Both are cheap insurance.