I'm willing to bet good money that this isn't the 'dwarf version'. LA probably gets these from Quality Marine like my old store did, we rarely got anything other than aculeatus. Besides, unless the perspective is way off, he looks fairly large (gonna guess it's a he but I could be wrong).
Do some research on keeping octopus, otherwise this little guy probably won't last long. The information is not hard to find at all. The first two weeks are when you will probably loose it.
On a more positive note, I have personally had the opportunity to care for many of these little guys. This is one of my favorite species because they are very active during the day and they will be very curious about you.