My take is that it's a 2001 Master with the LX14 (not custom) paint job. The Chorus groupset is much newer than that. It has the four sided tubing and a straight fork. She is also riding Speedplay pedals

This is the kind of bike that "the boss" gives to me to tune up or overhaul, as I really enjoy working on them.
Colnago was obsessed with fakes. If she wants, she can contact them in Italy with pictures and a serial number, and they can trace it back to the day that it was built, who built it, it's ownership, and any factory service history. They actually encourage owners to do this, as it will update their registry.