Notes uses a "rule of 50" convention for dealing with two-digit dates. Less than 50, the year is set to 20nn, greater than 49 is set to 19nn.
The JavaScript DateObject constructor does not adhere to this convention. If you pass it a two-digit year it always returns 19.
For example, if you perform @Year on a Notes date of 01/28/01 you receive 2001, while if you create a JavaScript Date object from 01/28/01 and call getYear(), you receive 1901.