Yes and no.
There's a wide range of actual supression behind the 'pinned' status and it's that suppresion figure more than the status that affects a squads responses.
In WinSPWW2 they'll be more likely to be at the high end of that range when pinned. Or better put, in WinSPMBT they'll tend to be more on the low end of that range. That has to do with added suppression from direct fire at a unit. In MBT that was rather low, in WW2 it isn't anymore. So in MBT firing at a pinned squad doesn't add that much extra suppression while in WW2 it does. Which means that in WW2 pinned units willtend to have more suppression and hence less OP shots, etc.
Narwan