Restoring from manual backup

I’ve tried copying my previously downloaded and saved content folder from a ghost 3 install into a fresh install of ghost 5 and after uploading and setting permissions the posts and images I restored aren’t showing up, I really should have used the json backup option but i didn’t think of doing it at the time, I have about 8 years worth of content now gone… please advise.

Is the Ghost V3 installation still available? And, what files do you have in content/data?