Make sure you remove the old holder and clean any corrosion that is lurking underneath it before you consider the job complete.
If you add a remote holder, look at adding spade lugs for the two wires near the mother board, and then put the holder near the coin door so you don't have to remove the backglass to change the batteries. The spade lugs are so you can remove the board easily without having to fish the battery holder thru the machine. Make sure you set up so you can't reverse polarity.