So the FedEx guy brought this today:

It looks correct. It had a return shipping label to Nordic, the manufacturer. I called them because I was curious as to whether it had any value to them. I explained that I bought it from a "picker" on eBay. They were very nice and said the 8310 is old and has little demand so they don't want my core back. They also mentioned that the one I got must be pretty old. I asked, therefore, if I should do anything special. They said no, sitting around doesn't hurt them, but to be safe turn it upside down and let all the fluid go to the top, flip it over again and let it run down. Do it 2 or 3 times. This will make sure the internal rust inhibitor mixes properly with the other fluids.
I'm going to pop it in over the weekend....