I bought a 165 and a 175 back in the day.
In comparison at the time, I did notice that the heatsink supplied with the 175 was different in design with a beefier heat sink and heat pipe assembly etc, compared to the 165?s.
IIRC the heatsink supplied with the 175 was identical to the one supplied with a retail FX-60.
Thing is, I did purchase one of the first 165?s to hit retail, so perhaps they changed it further down the production cycle to match the heatsink of the 175 (and subsequently the same as the FX-60?s).
Just FYI, you can use any s939 heatsink you like with the OEM FX-60. The only thing you?ll notice between the use of different heatsinks is their ability to cool the processor while idle and under load.