M-Audio Delta 66 and Omni I/O /w delta 66 differences

Hi,
I want to buy a used M-AUDIO delta 66 soundcard. On the internet I
saw 2 models :

M-Audio Delta 66
M-Audio Omni Studio Omni I/O with Delta 66

On M-Audio's web site there's no information about the Omni I/O.
Is there any differences between the current Delta 66 soundcard and the
one that came with the Omni I/O module (it seems an older card, it's
not the same color and it's writen 1999 on it). Will the current delta
66 work with this card (omni).

I would prefer to buy the one with the Omni I/O module since there's
volume knobs, unbalanced/balanced I/O, FX send and many more option on
it. Does M-Audio still sell this product? If not what was the retail
price of it and how old is it. Is it a better product than the current
Delta 66 module.

Does anyone have one of them and could give me experience feedback on
those products

Any other information will be very useful