We had one a couple auctions ago and noticed the same thing while we were researching. If I were a betting man I'd say the one with the filled in letters was produced later (not saying it's a reprint or modern or anything, more that it's a "type II" kind of situation) and is a photographic reproduction of the first as the image quality is lower. I would argue that ours was potentially a third version as our letters looked gray, though with the condition issues I could see arguing they're just a toned or soiled white.
