Don't need to fill any holes as there is a sufficient amount of wood between the new and old holes although it would only take a few minutes to plug them I guess, just line it up with the string holes, mark the centres and drill new ones. I just used a Dremel, took 5 minutes to fit.
That picture is intonated btw, there's another guy who fitted the same bridge on TalkBass and his B saddle looks further back than mine (well all of them do really), his actions looks to be very high though so maybe that's affecting intonation at the 12th fret. Pinched the pic here: