This, exactly. I also for example remember as a kid hearing mouthguards reduced concussions, but a paper from BMJ Sports medicine states. " The ability of mouthguards to protect against head and spinal injuries in sport falls into the realm of “neuromythology” rather than hard science.32 Reading the original studies cited as evidence for this effect reveals anecdotal claims that can best be described as bizarre rather than reflecting established medical principles. It is unlikely that a mouthguard would offer effective protection against brain or spinal cord injury, and the limited published data are not compelling in this regard nor does it accord with the known pathophysiology of such injuries. " http://bjsm.bmj.com/content/35/2/81
If it's a nice looking, comfortable helmet, great... but one helmet to the next is very unlikely to prevent a concussion.