When sites like Covers.com give historical line information, where do they tend to get those numbers? I'm assuming that they're using the closing line from somewhere. But since the lines change from book to book, is there such an animal as an "official" line?
There's no official line, but they are using their latest line update from Pinnacle for MLB. I believe they use Pinnacle for all sports, but I'm not 100% sure about that.
Yes turnip, covers is currently using Pinnacle closings. I say "currently" because they change books from time to time, but they have been using pinny for a while.