RathRyan
My game is BG/ToSC (patched) and I can confirm that the Ring at the FAI is where it's supposed to be, as my mage (Dynaheir) now wears it!
It can be a tad difficult to find it, as the "secret location" is very small, only a few pixels across. Use the "L" key to help locate the item.
Like I said, my game is a *patched* BG/ToSC and the ring *is* there.