All Model 3: HW2.5
Model S and X after September 2017: HW2.5
Model S and X between October 2016 and September 2017: HW2
Model S and X before October 2016: HW1
No reports of HW3 in the wild. Of course Elon’s dev car has it and presumably those of his inner circle and senior autopilot engineers have it too.