Unusual Barrel Mug

At a local Sal Army I found a set of 4 handles Barrel mugs that I haven't seen anywhere before and that I can't find on Ooga-Mooga or Tikiroom.net. I was wondering if anyone knows anything about it.

The barrel is green & patterned to look like woodgrain with 4 dark grey "metal bands" circling the barrel. The handle is green with a slight stick-like pattern on it and a thumb rest on top. The bottom has a square in the center marked "Made in Japan" with a raised section marked "N033" (the raised markings look like they were made by a label maker and the label was stuck onto the bottom of the original the mold was made from), the unlabeled area is woodgrained like the side and the outer rim of the bottom is bisque fired. The lip & inside are a cream color glaze. There are fine cosmetic crazing marks across parts of the mug, and one looks like it's handle was cracked but not broken before it was glazed.

I'll post pictures after I've gotten them developed.