Nothing new here.
Ben Rich's excellent book Skunk Works mentions that before Stealth 'bombers' were first used in anger, they were almost used on Gadaffi. Apparently the Colonel 's regime didn't warrant the revelation of what was a secret weapon back then. True secrecy is not even letting your opponent know that the secret exists. Anything else is Privacy.
Anyone who has seen Blackhawk down knows that when speed is of the essence, US doctrine is to use air assets to come in from above. With 2 possible outcomes (dismount and enter via the ground floor or come through the roof), potential opponents have to plan for both, dilluting their Concentration of Force(s). Maybe the ground troops were a diversion, maybe that was plan B if a Helo went down (which is about the only undisputed fact). Lots of 'maybes' and not enough to say if this was an assasination mission by design.
Finally, 'Zero Electro Magnetic radiation' may be a relative term. As the writer (of the book) is not a scientist, I think we can cut him some slack. Previous Stealth improvements have reduced emmitions by orders of magnitude. Suppose a normal, current generation helo emits 1000 units of noise/IR/RF and then defensive systems are looking for around 1000 units. If THEY doubled the sensitivity of sensors, 500 becomes the threshold. However, if I work realy hard and throw money, science and materials at the problem and reduce my emmissions by an order of magnitude (2nd generation), MY low noise/IR/RF helo emits 100 units, one fith of what the sensors are looking for. If I do it a second time (3rd generation), I'm emitting 10 units.
Arriving with 10, when they are looking for 500-1000 is zero emisions in my book, paricularly when you factor in other sources that are making more noise than you.