The real grit of this question depends on how the layout is wired.
IF it was wired in blocks you are probably in good shape, if it is wired in a Buss with no blocks you are likely to have have issues but they can be overcome.
Feel free to ask all the questions you have and someone will answer them.
When buying DCS I recommend Barry's book, available from the MTH website.
It contains a wealth of detailed and well explained material.