Hi Snowfan 😀 you are correct its not set in stone that Bae came to this world…
But I kind of think if Rumple made the curse, its logical that he would want to be transported to the exact place where Bae was transported to, Since Rumple is all about the fine details I think he would include this in the curse, to be 100% sure he would be able to find him…
Another point: (correct me if Im wrong) but I think Rumple said in the episode when talking to August about the dagger,“..its over Booth, my son would never try to use me, and he would know that this knife would not harness any power in this world,because there is no magic in this world,That is why he chose this place he didnt want me dabbling in it” Gold said something along those lines so this maybe is hinting that Bae is in this world.. BUT..this show tends to surpirse us (which I LOVE)…so it could be possible that Baelfire is in another world without magic or maybe even in another time…
I´m really excited to find out more about Bae!!