that is between you and the person who made the pack... The only time when it will be a question is if you try to trade official TGC packs, if you do that you will get in to trouble. Another thing is that if you do trade media packs make sure it is with the person who created the pack in question if you don't it is considered piracy and we don't take to kindly with those that adorn their eye patch while surfing the net..
So to sum it all up for ya:
Contact the creator of the pack(s) you wish to trade for and ask them, as they are the only ones who can really make that decision..
Cheers,
Dave