It certainly looks green. Again though, most people don't realize just how blue the dull blue solid Hammer was out of the box because so many of them greened up so much over time. If you want an example, check out the video of Del Ballard's unfortunate 10th-frame gutter ball. The blue Hammer he was using was SO much bluer than just about any dull blue I remember.
Anyhow, I don't know what to think. Obviously, we know that Hammer never released a green pearl Hammer to the public, at least not in the U.S. Could it be an overseas ball? Maybe, but I have no idea how common overseas releases were back then. It could have been a special edition ball for a certain tournament or something, but then I would've thought we would've seen/heard of them before now.
At the end of the day, my gut still tells me that it's a blue pearl that drastically changed color over the years, but we may never know. In any event, it would be fun to get it, resurface it, polish it up, and have a very unique ball sitting around.
