Here is a nicer image of what the acaeum.com calls the "B2 Keep on the Borderlands: Second Japanese print". However, the copyright dates are different from what tsrarchive.com calls the 2nd print: Japanese Dungeons & Dragons Archive.  So there is a 3rd print.

I've wondered whether the Japanese B2 was really first translated and published in 1982. Wouldn't the rulebook be translated first? But the Japanese rulebook didn't come out until 1985.

Probably an oversight on the early prints (note the date on the back of later print B2 does not match the front), or they had originally planned to release with B/X, but BECMI happened, which then caused a trade dress redo for late prints.

Incidentally, the listing for the Aussie Holmes cover Basic needs changing methinks. It sounds like the US version was printed with three inks (which would be inaccurate), and the Aussie two. AFAICT, the photo of the Aussie is printed black on blue paper (hopefully, someone with a copy can check on this). Perhaps the text can be corrected to:

"First Australian print.  Identical to the Fourth print US Basic Rulebook, with the exception that the cover is printed with black ink on blue paper, instead of the blue and black inks printed on white paper for the cover of the US version."

Aha! The Aussie definately has been printed two colors on white paper (cyan and black by the looks of it). Thanks for the photo.  

So, it appears both the US and Aussie are two colors on white paper. Just printed differently is all.

Odd thing about the US version though, from a printing perspective. I just checked the two copies I have under a magnifier, and while the inks do appear to be cyan and black, I see a moire pattern consistent with 4-color printing. Weird.