Yes, I have done it myself. When they had lifetime transfer at the time. It was 2 months after that transfer was complete, I had transferred the 10 months remaining of a year to a series 2.
You would need to get your remaining Tivo up and connect to service to show them it is still working.
Original S1 (Recycle Heaven)
Series 2 (PLS, sold)
TiVo HD (XL, PLS, "652")
Juliet Basic (4XL, PLS)
The TiVo Apocalypse begins on Sat 2013 Feb 16 00:00 GMT!