I don't know their exact run numbers, the zombie heads are actually sold seperately. But if I remember right I saw one a few months ago on E-bay go for around 80 if I remember right. And I think I saw one on YJA not too long ago and those are the only 2 I've seen for sale in a long time. Also, I think there are 2 versions.
I actually had both zombie heads(silver and regular) with the idea that I would get my hands on the dogs easy. Never happened. Still looking. It's the hardest to obake dog to get by far.