Why not check it. Personally I don't put stock in anything working like it should in this horrible world of outsourcing.
Get a cheap or use one you have hygrometer and perform a salt test. Once that small hand held unit is calibrated put it in the 1588 and see how accurate it is.
Salt test:
Milk/juice or whatever cap filled with salt. Add drops of water until saturated. I poor off any standing water.
Put hygrometer and cap in sealed container and wait minimum of four hours. Six is better. I use a quart Ziploc bag and provide small pillow of air.
At end of time and hygrometer reading has been stable, take the reading and subtract it from 75. That is your calibration #. This number you always add to the readings for true RH. Your unit is calibrated.
Ex. your reading is 86% RH. 75-86= -11. Your calibration # is -11. You'll always add that number to your readings for true RH. Adding a negative umber is same as subtraction.