It shouldn’t normally be an issue, Poser and Studio both have defined scales (8’ = 1 Poser Unit, 1cm = 1 DAZ unit) so Studio knows exactly what size to load things in as, whether they be PZ3, PP2 or CR2 - it wouldn’t make much sense for items to load at a different size to the core figures, whether they be the Poser G2s or the DAZ Gen 4s or Genesis.
However ISTR there were a handful of Poser designers who tried to standardise on a different scale a while back so there may be a small number of PZ3s out there which use that and therefore load smaller. And for non-PA freebie items all bets are off as you don’t know whether the creator was even aware of the scaling conventions.