I was hoping that a few of you would recognize it. When I first saw the CL ad, I thought it was a scam initially, since it listed an '8 bit Micron card', mentioned that it was a collectors item and had a picture of the back that showed an ethernet card. As a result of this supposition, I sat on the information for a few days before contacting the seller.
Yes, with the optional and very rare, grayscale adapter kit, this card supports internal grayscale. Note the extra white connector, which is for the adapter's wiring harness and is described in the accompanying instruction book. Unfortunately the extra kit was not installed in this computer. I guess you can't have everything - but if you keep your eyes open and with a bit of luck, the cool stuff is still out there.
On a related note, I am always on the lookout for a reasonably priced Micron internal grayscale adapter kit...