Twoup -
Part number 50377-07A is the complete setup of Crested boards and mounting brackets. They are for the '07 and later model FLSTN. Only mount brackets listed for the '05 FLSTN are part number 50400-05, but these are for the standard passenger boards and I don't know if they would attach to the Crested boards. By the pictures it appears they might. Go to a dealer and see if they will match up. Shouldn't have to order them to find out, most dealers have them hanging on the wall.
Good luck, dorr