For us with all Scotty post mount rod holders and accessories.  When fastening the mounting bracket to the boat, make sure the Scotty logo is reading upright when looking form inboard.  This ensures secure locking with the rod holder (fasteners not included).  For rail mounting, consider adding Scotty part 242 which is their rail adapter kit.  This is the non-locking version.  See Scotty part 241-L for the locking version of this base.

This color of the bracket is black.