What should I look for?

[1984 GT]

I'm going to purchase a 1988 mustang 8.8 rear-end assembly to replace the 7 1/2 rear in my 1984 tomorrow.

What should I look for to make sure it's in good shape? How can I tell if the posi is working? How do I verify what gears are in it?

Next....is the swap a job a person with limited mechanical experience should try?

Thanks.