Hi Junior.nar. It's not really OK. Distribution of models should be as per the creators requirements. Sometimes they say that the models may be freely distributed, but often they say not to be distributed other than downloaded from their own web site.
David's offer to download models from links you find is probably stretching a point but the intention seems reasonable.
Asking for models from people's collections is definitely not OK.
Let me know if you've got any questions.
Cheers
Mark