Good question. I just plugged my 996P2 in without any drivers and it recognized the radio as a Uniden serial device.
Downloaded my 996XT systems to it out of Freescan (after adding one P2 site) and off to the races.
It must be the same. I have a 536 and probably installed these drivers back then.
Mark
536HP/HP1e/HP2e/996P2/996XT
996T/396XT(2)/PSR800/PRO668