I can't answer your question related to refurbished verse reconditioned, but I can offer my opinion.
I have purchased "B" Stock Receivers from accessories4less a couple of times (1 Onkyo and 1 Marantz) with no issues. They both came with a 1 year warranty which I never needed to use. The warranty is is not as long as one from "A" stock, but I figure most issues would happen during that 1st year.
I have recently helped my parents swap out 2 older receivers that they purchased back in 1991. Both had their own issues, an they were looking for HDMI. The problem is that the new receivers have video out issues that Onkyo Support is still not able to fix. The receiver you mention is not one of the affected model #'s, so no worries there.
In short, my opinion, you can have issues with A Stock or B Stock. Just make sure that you are buying from an authorized dealer with a valid warranty.