I think I found something. If you view according to account history you can see the action transactions, reblogging is a custom json transaction that falls under follow. will update once I can confirm. haha just wanted to reply it seemed a bit exciting.
edit: nvm @sambillingham posted a nice explanation of what I found also.
I read something about reading through the custom json transactions to find data. That would be nice if the reblogged_by could be retrieved this way.