My ST60 reads both apparent and true wind speed. I also have the ST60 knotmeter too. There is definably a difference in the reading, direction etc when on apparent vs true.
I do not have it hooked to a GPS, which might yield something slightly different when I am in a tide running here in puget sound, but there is a difference in what it reads as is.
She drives me boat,
I drives me dinghy!