Some good news - after removing the cover place and scrubbing the jack contacts with an eraser and then applying Deoxit and scrubbing more, I have the bass making sound.
That Model One pickup is pretty hot, and has just a bit of the "woofiness" associated with the mudbucker. All in all, not a bad sound. Might make a good pair with an Artec in the original neck position. Looking at the Model One from the side, the installation doesn't impress me; it looks like it's not fully recessed into the body by about 1/16". That can be fixed.
I had the chance to compare it with my recently built Epi EB-0 and there definitely is more high end in the Epi sound. Also, the Epi is more of a slab body and the Gibson has contours all around the edges. I see that they put the same emblem below the Epi name as they used on the original Gibson.
Here's the wiring...4 leads from the pickup...
Here are the bodies and headstocks...Gibson on the right in both pix. You can see that the Gibson body has more contour around all the edges than the Epi body.