It seems to be correct and wrong 
It scrolls through all those Registry entries and gives bunch of list. When I manually verify a few computers, those having 2 monitors get more than 2. It may be because of stale entries in registry the fact that the system used other monitors some time ago. Effectively, one computer was attached to a couple of monitors which are replaced by new two monitors. So, this query gets all 4 of them. Is there a way to filter out non-active ones?