You have several download options at the device level: Device, Properties and Signals, Parameters, and Update Device Download Status.
Device: downloads the device as well as properties and signals and parameters
Properties and Signals: downloads Properties and Signals only
Parameters: downloads parameters only
If you decide to download a device and during the download you notice a parameter value that is incorrect in the database, you can deselect the parameter for download, download the device, and then modify the value online. You cannot modify a value during the download.