OK, so there is no place to discuss other tools generally, and Pnuematics in particular. I went ahead with the purchase of the older compressor with the questionable tank and the extra "new" tank to go with it for $200.00 the picture from original owner is below. (I haven't had the chance to take it off of my truck yet to get my own pictures.)
It turns out to be a 2 stage Kellogg-American built between 1910 and 1925 (http://kellogg-american.com/company/). I did get a picture of the makers plate, although it isn't very good.
The owner had quite the time locating the tags on