Toner doesn't get Lightfast ratings, they are for dyes and pigments and inks.
How long a toner based print will hold up under direct sunlight depends entirely on the location and how much sunlight it is exposed to. A print in the sun of New York will last much longer than one in Florida.
In reality, the amount of Magenta (Red) used is the real deciding factor due to its place on the visible spectrum. It fades at a rate measured in months (In Florida sun) as opposed to years.
Can someone tell me lighfastness of toner used in versant 80 press ? I am a digital artist want to print at local printer and need to know if I need to do a varnish to enhance lightfastness. Nobody at XEROX custormer support could help Thanks