If your question is "Will a PCIe 2.0 card run in a PCIe 1.0 slot (or the reverse)?", the answer is that it is supposed to run by specification. It should negotiate properly, and the slot or the board should synch down to the 1.0 spec of the other.
That is indeed my question. I knew that it was supposed to be all-direction compatible like USB is, the only concern I had is the fact that those cards take all their power from the slot. I thought that PCI-E 2.0 had more power available? And maybe those need it?