To accomplish a coup takes a lot more than a few gunmen inside a palace. It takes literal national or at least military mobilization. Even failed coups leave considerable traces in this era of 24 hour media. What the article I linked to pointed out was that there was no shutdown of media or internet access which is pretty much step 1 whenever there's an attempt. Gunshots are flimsy evidence in Riyadh.to be fair no source is completely reliable at the moment