Do I ask for rental histories?

[John S Lewis]

So I think I found a good deal.  The owner says he's made money and now wants to get out of the biz and sell down his holdings in the next 5 years.  He also claims the property I'm looking at is always rented.  Then I noticed on craigslist that he has ad's for the place to be rented.  Is it a normal course of due diligence to get rental records?  It's possible the leases are up I guess.  But of course I want to be sure.  Thanks.