No, you won't have it in March yet. You will have standard RFID keycards that opens your door. This is just in preparation, SORT OF....they had plans to do the RFID locks long before the fastpass+ thing even came up -- it allows them to automatically update keycard room information (like if you need to move from one room to another, you no longer have to go to the check-in, they just change the code on the new room's lock to now work with your key)...This is something a lot of hotels are doing, not just WDW....
There is no announcement of when the full Fastpass+ program with wristbands will roll out, but its not expected until June (or later)...their beta testing has been getting a TON of complaints and bad feedback at their focus groups (I was in one about a month ago and nobody had good things to say about it)...so they will probably still be making lots of tweeks and changes before they roll anything out