If both systems are on the same software, same patch levels and keycoded similar then a restore of the 200 programming may work. A voicemail restore should work fine but I don't know about the telephony programming. The only real difference between a MSC1A and MSC1B is the lack of DS30 expansion port and two MBM connectors, no functional code differences. That being said, I've never tried it. Logic says the programming should restore, but this is Nortel so logic doesn't always apply. Since you have a replacement system, no harm in trying.