I sent you high resolution images of my Matrox Parhelia AGP 128 and Matrox Parhelia PCI-X 256. Unfortunately, I have the same AGP 2/4/8X model shown on Wiki. Some of the component layout is a little different as well. If you can find another image your exact card which indicates a part number of the missing inductor, that would be best. On my card, not all the inductors are the same.
On my card, the inductor in the place of where your missing inductor is, is labeled LCD104-6R8A 0228. If the 104 is the inductance value code, I think that is a 100 mH inductor. 103 is a 10 mH inductor, and 102 is a 1 mH inductor. At least that is why my LCR meter shows for some spare inductors I have in my bin. I'd see if you can find the exact datasheet though.
Did you specifically not want a Parhelia keyed for 2X as well? I'm surprised that your Parhelia AGP 128 is keyed for 4X/8X only. Is it the 256 MB version? I thought all 128 MB versions were keyed for 2/4/8x.
Plan your life wisely, you'll be dead before you know it.